In order to answer you question about pro's&con's, we need to know your intentions. IMHO, putting an LT1 in place of the Porsche engine just gives you the privilege of buying expensive Corvette engine parts instead of expensive Porsche parts. If you are going to use your car for racing, this might make sense. If you're going to use it for normal street use, you're better off just getting a regular 327 or 350 GM engine. This will get you the majority of the LT1's performance, but give you the reliability & cheap parts of the standard small block. If you go to
www.924.org, there is a forum just for discussing performance upgrades.