No, crosslinked (XL) automotive wire is a much higher quality of wire than PVC plastic insulated primary wire that is commonly found at parts stores. It's insulation can withstand much higher temperatures. It is explained here:
http://www.automotivewire.info/automotiveprimarywire.htm .
This illustrates why parts stores probably don't carry it: the average person who works on cars doesn't know the difference so stores figure they would never sell any of it because people would just buy the cheaper PVC insulated wire.
