diff --git a/commands/CmdE.c b/commands/CmdE.c
index df4bc2f1..f3b0a148 100644
--- a/commands/CmdE.c
+++ b/commands/CmdE.c
@@ -1096,7 +1096,7 @@ CmdExtract(
 	"lumped			estimate lumped resistance",
 	"labelcheck		check for connections through sticky labels",
 	"aliases		output all net name aliases",
-	"unique			ensure unique node names during extraction",
+	"unique	 [notopports]	ensure unique node names during extraction",
 	"resistance		extract resistance (same as \"do extresist\")",
 	NULL
     };
@@ -1403,6 +1403,7 @@ CmdExtract(
 		TxPrintf("%s label check\n", OPTSET(EXT_DOLABELCHECK));
 		TxPrintf("%s aliases\n", OPTSET(EXT_DOALIASES));
 		TxPrintf("%s unique\n", OPTSET(EXT_DOUNIQUE));
+		TxPrintf("%s unique notopports\n", OPTSET(EXT_DOUNIQNOTOPPORTS));
 		TxPrintf("%s resistance (extresist)\n", OPTSET(EXT_DOEXTRESIST));
 		return;
 #undef	OPTSET
@@ -1433,9 +1434,19 @@ CmdExtract(
 		case DORESISTANCE:	option = EXT_DORESISTANCE; break;
 		case DOLABELCHECK:	option = EXT_DOLABELCHECK; break;
 		case DOALIASES:		option = EXT_DOALIASES; break;
-		case DOUNIQUE:		option = EXT_DOUNIQUE; break;
 		case DOEXTRESIST:
 		case DOEXTRESIST2:	option = EXT_DOEXTRESIST; break;
+		case DOUNIQUE:
+		    if (argc == 4)
+		    {
+			if (!strncmp(argv[3], "notop", 5))
+			    option = EXT_DOUNIQNOTOPPORTS | EXT_DOUNIQUE;
+			else
+			    TxError("Usage:  extract do unique [notopports]\n");
+		    }
+		    else
+			option = EXT_DOUNIQUE;
+		    break;
 		case DOLOCAL:
 		    /* "extract do local" and "extract no local" are kept for
 		     * backwards compatibility, but now effectively implement
diff --git a/doc/html/extract.html b/doc/html/extract.html
index 101ab739..b1926498 100644
--- a/doc/html/extract.html
+++ b/doc/html/extract.html
@@ -102,16 +102,17 @@ Circuit netlist extractor
 			but will usually just slow down processing by commands
 			like "ext2spice" that use the .ext file contents, so it
 			is disabled by default.
-		  <DT> <B>unique</B>
+		  <DT> <B>unique</B> [<B>notopports</B>]
 		  <DD> (Added in magic version 8.3.594) This setting replaces
-			the use of the command option "extract unique".  Instead
-			of changing labels in the design, unique labels are
-			generated for the duration of the extraction, and then
-			reverted back to the original text.  The "extract unique"
-			command option is maintained for backwards compatibility.
-			Note the difference:  "extract unique" is a command that
-			runs immediately, and cannot be undone;
-			"extract do unique" is an option setting for "extract".
+			the use of the command option "extract unique" (and
+			"extract unique notopports").  Instead of changing labels
+			in the design, unique labels are generated for the duration
+			of the extraction, and then reverted back to the original
+			text.  The "extract unique" command option is maintained
+			for backwards compatibility.  Note the difference:
+			"extract unique" is a command that runs immediately, and
+			cannot be undone; "extract do unique" is an option setting
+			for "extract".
 		  <DT> <B>resistance</B>
 		  <DD> (Added in magic version 8.3.597) This setting replaces
 			the use of the standalone command "extresist".  The
diff --git a/doc/html/extresist.html b/doc/html/extresist.html
index b69e256b..7d33854a 100644
--- a/doc/html/extresist.html
+++ b/doc/html/extresist.html
@@ -43,8 +43,7 @@ information.
 	   <DD> With no value given, returns the current delay time threshold
 		used to determine if a network will or will not be analyzed for
 		resistance extraction, in picoseconds.  The default
-		<B>mindelay</B> value is zero, indicating that delay time is
-		not used for determining extraction.  If <I>value</I> is given,
+		<B>mindelay</B> value is 1ps.  If <I>value</I> is given,
 		then set the delay threshold to <I>value</I> picoseconds.
 	   <DT> <B>minres</B> [<I>value</I>]
 	   <DD> With no value given, returns the current absolute resistance
diff --git a/extract/ExtBasic.c b/extract/ExtBasic.c
index 3885ac80..a9ca1fdd 100644
--- a/extract/ExtBasic.c
+++ b/extract/ExtBasic.c
@@ -629,6 +629,8 @@ extSetResist(reg)
 
     for (n = 0; n < ExtCurStyle->exts_numResistClasses; n++)
     {
+	ResValue resnew, restot;
+
 	reg->nreg_pa[n].pa_area = area = extResistArea[n];
 	reg->nreg_pa[n].pa_perim = perim = extResistPerim[n];
 	if (area > 0 && perim > 0)
@@ -639,8 +641,15 @@ extSetResist(reg)
 	    if (v < 0) s = 0; else s = sqrt(v);
 
 	    fperim = (float) perim;
-	    reg->nreg_resist += (fperim + s) / (fperim - s)
-				    * ExtCurStyle->exts_resistByResistClass[n];
+	    resnew = (fperim + s) / (fperim - s) *
+		    ExtCurStyle->exts_resistByResistClass[n];
+	    restot = reg->nreg_resist + resnew;
+
+	    /* Check for integer overflow.  There is no point in trying
+	     * to accommodate huge resistance values for an estimate.
+	     * The value just saturates at the maximum integer value.
+	     */
+	    if (restot > 0) reg->nreg_resist = restot;
 	}
 
 	/* Reset for the next pass */
diff --git a/extract/ExtCell.c b/extract/ExtCell.c
index 994b47cb..46be433e 100644
--- a/extract/ExtCell.c
+++ b/extract/ExtCell.c
@@ -76,14 +76,10 @@ void extHeader();
  */
 
 Plane *
-ExtCell(def, outName, doLength)
+ExtCell(def, outName, isTop)
     CellDef *def;	/* Cell being extracted */
     char *outName;	/* Name of output file; if NULL, derive from def name */
-    bool doLength;	/* If TRUE, extract pathlengths from drivers to
-			 * receivers (the names are stored in ExtLength.c).
-			 * Should only be TRUE for the root cell in a
-			 * hierarchy.
-			 */
+    bool isTop;		/* If TRUE, cell is the top level cell */
 {
     char *filename;
     FILE *f = NULL;
@@ -116,7 +112,7 @@ ExtCell(def, outName, doLength)
     }
 
     extNumErrors = extNumWarnings = 0;
-    savePlane = extCellFile(def, f, doLength);
+    savePlane = extCellFile(def, f, isTop);
     if (f != NULL) fclose(f);
 
     if (extNumErrors > 0 || extNumWarnings > 0)
@@ -476,13 +472,10 @@ ExtRevertSubstrate(def, savePlane)
  */
 
 Plane *
-extCellFile(def, f, doLength)
+extCellFile(def, f, isTop)
     CellDef *def;	/* Def to be extracted */
     FILE *f;		/* Output to this file */
-    bool doLength;	/* TRUE if we should extract driver-receiver path
-			 * length information for this cell (see ExtCell
-			 * for more details).
-			 */
+    bool isTop;		/* TRUE if the cell is the top level cell */
 {
     NodeRegion *reg;
     Plane *saveSub;
@@ -493,8 +486,19 @@ extCellFile(def, f, doLength)
     /* If "extract do unique" was specified, then make labels in the
      * cell unique.
      */
+
     if (ExtOptions & EXT_DOUNIQUE)
-	extUniqueCell(def, EXT_UNIQ_TEMP);
+    {
+	if (ExtOptions & EXT_DOUNIQNOTOPPORTS)
+	{
+	    if (isTop)
+		extUniqueCell(def, EXT_UNIQ_TEMP_NOPORTS);
+	    else
+		extUniqueCell(def, EXT_UNIQ_TEMP);
+	}
+	else
+	    extUniqueCell(def, EXT_UNIQ_TEMP);
+    }
 
     /* Prep any isolated substrate areas */
     if (ExtOptions & EXT_DOEXTRESIST)
@@ -524,7 +528,7 @@ extCellFile(def, f, doLength)
     ExtResetTiles(def, CLIENTDEFAULT);
 
     /* Final pass: extract length information if desired */
-    if (!SigInterruptPending && doLength && (ExtOptions & EXT_DOLENGTH))
+    if (!SigInterruptPending && isTop && (ExtOptions & EXT_DOLENGTH))
 	extLength(extParentUse, f);
 
     UndoEnable();
diff --git a/extract/ExtMain.c b/extract/ExtMain.c
index bdc594af..ec1f475d 100644
--- a/extract/ExtMain.c
+++ b/extract/ExtMain.c
@@ -473,6 +473,19 @@ ExtUnique(rootUse, option)
     /* Fix up bounding boxes if they've changed */
     DBFixMismatch();
 
+    /* Because the "extract unique" does the same thing as "extract do unique"
+     * but the options may be different, disable "extract do unique" when
+     * "extract unique" is run, on the assumption that no user would
+     * intentionally use both methods.  If "do unique" was set and got
+     * disabled, then flag a warning.
+     */
+    if (ExtOptions & EXT_DOUNIQUE)
+    {
+	ExtOptions &= ~EXT_DOUNIQUE;
+	TxPrintf("Warning:  Extract option \"do unique\" disabled because "
+		"\"extract unique\" was run.\n");
+    }
+
     /* Mark all defs as being unvisited */
     (void) DBCellSrDefs(0, extDefInitFunc, (ClientData) 0);
 
diff --git a/extract/ExtUnique.c b/extract/ExtUnique.c
index 93726a13..82f4772d 100644
--- a/extract/ExtUnique.c
+++ b/extract/ExtUnique.c
@@ -66,6 +66,8 @@ static char rcsid[] __attribute__ ((unused)) = "$Header: /usr/cvsroot/magic-8.0/
  *	    label.  This way, the unique label form can be used by the
  *	    extraction code but labels (and port indexes) can be reverted
  *	    afterward, and no permanent change is made to the circuit.
+ *	Option EXT_UNIQ_TEMP_NOPORTS is a combination of EXT_UNIQ_TEMP and
+ *	    EXT_UNIQ_NOPORTS.
  *
  * Results:
  *	Returns the number of warnings generated.
@@ -226,8 +228,9 @@ extMakeUnique(def, ll, lreg, lregList, labelHash, option)
     text = ll->ll_label->lab_text;
     if (option == EXT_UNIQ_ALL || option == EXT_UNIQ_TEMP)
 	goto makeUnique;
-    else if ((option == EXT_UNIQ_NOPORTS || option == EXT_UNIQ_NOTOPPORTS)
-		&& !(ll->ll_label->lab_flags & PORT_DIR_MASK))
+    else if ((option == EXT_UNIQ_NOPORTS || option == EXT_UNIQ_NOTOPPORTS ||
+		option == EXT_UNIQ_TEMP_NOPORTS) &&
+		!(ll->ll_label->lab_flags & PORT_DIR_MASK))
 	goto makeUnique;
 
     cpend = strchr(text, '\0');
@@ -326,7 +329,8 @@ makeUnique:
 	    saveLab = *lab;
 
 	    /* Flag this label as having been modified */
-	    if (option == EXT_UNIQ_TEMP) flags |= LABEL_UNIQUE;
+	    if ((option == EXT_UNIQ_TEMP) || (option == EXT_UNIQ_TEMP_NOPORTS))
+		flags |= LABEL_UNIQUE;
 
 	    DBRemoveLabel(def, lab);
 	    DBPutFontLabel(def, &saveLab.lab_rect,
diff --git a/extract/extract.h b/extract/extract.h
index 19242f65..43cd687b 100644
--- a/extract/extract.h
+++ b/extract/extract.h
@@ -76,6 +76,7 @@ extern const char * const extDevTable[];
 #define	EXT_DOLABELCHECK	0x040	/* Check for connections by label */
 #define EXT_DOALIASES		0x080	/* Output all node aliases */
 #define EXT_DOEXTRESIST		0x200	/* Do full R-C extraction */
+#define EXT_DOUNIQNOTOPPORTS	0x400	/* Ignore top cell ports w/EXT_DOUNIQUE */
 
 extern int ExtOptions;		/* Bitmask of above */
 extern char *ExtLocalPath;	/* If non-NULL, location to write .ext files */ 
@@ -86,6 +87,7 @@ extern char *ExtLocalPath;	/* If non-NULL, location to write .ext files */
 #define EXT_UNIQ_NOPORTS	2
 #define EXT_UNIQ_NOTOPPORTS	3
 #define EXT_UNIQ_TEMP		4	/* Used only with "EXT_DOUNIQUE" */
+#define EXT_UNIQ_TEMP_NOPORTS	5	/* Used only with "EXT_DOUNIQUE" */
 
 extern bool ExtTechLine();
 extern void ExtTechInit();
diff --git a/resis/ResMain.c b/resis/ResMain.c
index 9c90ac53..a30f5fdb 100644
--- a/resis/ResMain.c
+++ b/resis/ResMain.c
@@ -1382,8 +1382,6 @@ ResExtractNet(node, resisdata, cellname)
     }
     DBReComputeBbox(ResUse->cu_def);
 
-    ExtResetTiles(scx.scx_use->cu_def, CLIENTDEFAULT);
-
     /* To avoid issues with overlapping stacked contact types and	*/
     /* double-counting contacts on multiple planes, erase the top	*/
     /* contact layers of all contacts.  ExtFindRegions() will still	*/
diff --git a/resis/ResReadExt.c b/resis/ResReadExt.c
index 12fc35e4..6b2cbedc 100644
--- a/resis/ResReadExt.c
+++ b/resis/ResReadExt.c
@@ -519,6 +519,7 @@ ResReadNode(int argc, char *argv[])
 {
     HashEntry	*entry;
     ResExtNode	*node;
+    int noderesist;
 
     entry = HashFind(&ResNodeTable, argv[NODES_NODENAME]);
     node = ResExtInitNode(entry);
@@ -526,7 +527,10 @@ ResReadNode(int argc, char *argv[])
     node->location.p_x = atoi(argv[NODES_NODEX]);
     node->location.p_y = atoi(argv[NODES_NODEY]);
     node->type = DBTechNameType(argv[NODES_NODETYPE]);
-    node->resistance = atoi(argv[NODES_NODERES]);
+    noderesist = atoi(argv[NODES_NODERES]);
+    if (noderesist < 0) noderesist = INFINITY;
+    /* Make sure node resistance is in units of milliohms */
+    node->resistance = (float)noderesist * (float)ExtCurStyle->exts_resistScale;
 
     if (node->type == -1)
     {
diff --git a/resis/ResRex.c b/resis/ResRex.c
index 7f9743cb..51c77528 100644
--- a/resis/ResRex.c
+++ b/resis/ResRex.c
@@ -218,11 +218,11 @@ ResInit()
 	/* Defaults:
 	 * (1) rthresh:  Only extract networks with a lumped resistance > 10 ohms
 	 * (2) minres:   Prune resistors < 1 ohm when possible
-	 * (3) mindelay: Do not gate extraction based on calculated delay.
+	 * (3) mindelay: Only extract networks with a calculated delay > 1 ps
 	 */
 	resisdata->rthresh = 10000.0;
 	resisdata->minres = 1000.0;
-	resisdata->mindelay = 0.0;
+	resisdata->mindelay = 1.0e9;	/* 1ps = 1.0e9zs
 	resisdata->frequency = 10e6;	/* 10 MHz default */
 
 	HashInit(&ResIgnoreTable, INITFLATSIZE, HT_STRINGKEYS);
@@ -407,7 +407,8 @@ typedef enum {
 		Tcl_SetObjResult(magicinterp,
 			Tcl_NewDoubleObj((double)resisdata->rthresh));
 #else
-		TxPrintf("Minimum resistor threshold is %g.\n", resisdata->rthresh);
+		TxPrintf("Minimum resistor threshold is %g mohms.\n",
+				resisdata->rthresh);
 #endif
 	    }
 	    return;
@@ -1907,9 +1908,17 @@ ResWriteExtFile(celldef, node, resisdata, nidx, eidx)
 
     if (!(ResOptionsFlags & ResOpt_RunSilent))
     {
-	TxPrintf("Adding  %s; (Tnew = %.2fps ; Tmin = %.2fps)\n",
-		     	node->name, resisdata->rg_Tdi * Z_TO_P,
-			resisdata->mindelay * Z_TO_P);
+	float ftdi, fdmin;
+
+	ftdi = resisdata->rg_Tdi * Z_TO_P;
+	fdmin = resisdata->mindelay * Z_TO_P;
+
+	if ((ftdi < 0.01) || ((fdmin < 0.01) && (resisdata->mindelay > 0)))
+	    TxPrintf("Adding  %s; (Tnew = %.2ffs ; Tmin = %.2ffs)\n",
+		     	node->name, ftdi * 1000, fdmin * 1000);
+	else
+	    TxPrintf("Adding  %s; (Tnew = %.2fps ; Tmin = %.2fps)\n",
+		     	node->name, ftdi, fdmin);
     }
 
     for (ptr = node->devices; ptr != NULL; ptr = ptr->nextDev)