i agree with M54.the C4 dont appeal to me neither.id rather have the 80 body lines.id go for the 80 vette but only if it has the 350ci engine and not the 305.you can find out which engine it has by looking at tne VIN number.LG4 = 305ci and L82 = 350ci.as far as modifying the engine,itll pretty much will depend on how much money you wanna put in the engine.the GM350 is so easy to modify and tons of aftermarket parts to make tons of HP.
i would go with old school highrise manifold anf 4 barrel carb just to keep the nostalgia look and effect.