[Simplypanda]

The Z can gain as much horsepower as the M3Turbo or even more. The restriction I am not sure how to take that off. Ask around in one of the performance shops. Most turbo appliacation says 8 psi, but you can put more for more horsepower. I believe Turbonetics turbo charger can boost much more but they just tested it at 8 psi. And when you say specs do you mean the specification sheet for the Zs? I do not believe the 2004 model is faster than the other models. If I am correct the newer models should have more horsepower, but I don't think they do I think they justs came out with better exterior peices like taillights and such.