Okay,
Here's what I have in mind.
R32 - any as it will be changed.
R36 engine - 296bhp out of the box - doesn't weigh any more than the R32 lump.
DSG
7 speed box if poss. - stronger than the 6 speed out of the box with a longer final drive. HGP do stronger internals and clutchpacks.
Twin scroll or twin turbo's for 600+bhp
Completely gut the interior and build up with carbon and alcantara lightweight parts
Carbon bucket seats
Race suspension and cage
Aim for a sub 1300kg car with 600+bhp.
Downsides - haldex 4wd is no real substitute for full 4wd, but it can be adapted to suit.
Investment will probably bankrupt me for a new road car.
I do like some of the alternatives though. Keep them coming