I've started the planning and design stages of a similar project. I would say stick with 964 4wd drive train and an STI motor in the back for easy fab. For 2wd domination, grab an ls6 and a g50 mid mounted and call it a day. For good tube chassis brain fodder start with the rorty design chassis and aim towards the ultima gtr chassis. For grins I've considered hacking the side pods off an ultima gtr chassis and tossing it under a 1303 body, maybe that will be my next setup