do you just road race or drag as well?
if you road race alone, get the lightest, Fidanza. If you drag don't get the lightest b/c you need inertia for launching, although mrtomcat pulled off a 1.85 s 60' with the Fidanza (and tons of skill).
if you plan to go turbo, don't go much lighter than stock. You don't want to lose boost between shifts and too light of a flywheel will hurt you.