Igor, do you think putting bolt ons on the stock Z by themselves produce any measurable gains? or is it just a waste of money? Thanks bro.

Well, there is a wide array of bolt-on modifications, as well as bolt-off....

Take the catalytic converters out and you'll see a gain.

A supercharger / turbo kit is a bolt-on for the most part.

In the big picture, the exhaust, headers, intake, and lack of cats do not make too big of a difference (on an otherwise stock car).

The best and cheapest performance modification is stripping the interior.