Adam's from Z1 performance on my question about gains on stock na cars:
"yes, there would certainly be gains to be had on a stock car as well...how much, will certainly vary car to car. Furthermore, it would serve as the basis for future mods.
Just an anecdotal example. With my mods (intake exhaust, cats, y pipe, pulley), I had my car flashed. Got about 12 whp and around 11 ft lbs, as well as smoothing out the curve. Car ran that way for 2 years, then we installed the UTEC - got the additional gains you see above. While that does not mean you will get 24 whp and 20 ft lbs, you will get gains
adam"