if you are not looking for cheap tuning you can go to any online aftermarket store or any body shops and you can tune the car for maximum speed, you can put a cold air intake change the manifold a slip differential and for better suspension you can add sway bars and coils over the suspension, but for power add a cold air intake, cat back exhaust system many ways of optimizing power to an engine but never use nitrous, very harmful to the engine cause great wear to the cylinders damages well over 3 k, so check in with any auto supply stores and they will help you.