I would say what Sandeep mentioned, but with turbo alu trailing arms to give you the extra strength and track width for hard circuit driving circumstances (doing the curb stones and all).
The extra width is very benificial for rear roadholding in bends at speed or under acceleration.
I am still missing the proper coil-over front and rears though. For 944's there are excellent 'ideal' rear solutions, but for front the existing coli over ones on the market today are not totally to my liking as far as 'ideal' goes. A modified 944 solution could be great, but probably $$..
For 944 (from
www.intrax.nl):