xp FTWIt's a pretty straightforward tuner. Just follow the on--screen instructions when you're making your custom tune. You can get more advanced custom tunes from the guys over at the Sniper forums, or from some of the members here in MM. But if you have Vista, it's a pain in the ass. At least it is on my computer.
Sniper allows you adjust your car on your own for the mods that you have through a very simple to use, user friendly interface without having to wait and pay for someone else to create a new tune for you.