Custom built 3L with an intercooled turbo.
An LSD (TorSen or Quaife)
Stage 3 or 4 axles with the forged hubs.
However to be honest I'd just do a simple 3L SVT swap with LSD and then pick a real car to make power with. This platform CAN NOT put any power down so any serious power is really just wasted effort.
Besides it's FWD and no FWD car ever drives the right wheels.
Oh yeah. Better brakes are a good idea and NOT just the fronts!
