I have a 94 GSR and I bought a skunk2 ECU and I noticed a big difference. It raised my redline from 8000rpm to 9500 rpm. It also made my car run richer, and the shop I got it from tld me that the next thing I should buy is a V-TECH controller, to help the ECU do its job better and more accurate. I have only had it in for a couple days but the shop I got it from said there is no problems with this, and it shouldn't be a problem.