Personally, if your tuner is worth anything at all, I'd get the Pro Racer software and spend an hour or so with your tuner dialing in the car...both on the dyno and on the road. Ultimately, you will only end up changing a few tuning parameters to get the car where you want it...thus you can see why there is a mail order market for these sorts of things. If it were very complicated, there would be no way to do mail order tunes (generally speaking). I purchased all my stuff from Sean Roe without any drama. It is very easy software to use for just tinkering with a N/A tune and you can easily reset everything back to stock if you head down the wrong path. Plus once you get into the software, its interesting to see all the other engine parameters and how the engine is sort of tied together through the PCM. Someone once posted "I don't care to know how it works, just that it works." Well, I'm at the other end of the spectrum. I want to know how it works so I understand why it works.