the best route is to get an X3 programmer. We have a sponsor on here who does alot of tunes for alot of people (including me ^_^) The guys name is james henson and his site is
www.hensonperformance.com He can hook you up with an X3 programmer and 3 custom tunes for $389. I personally got an 87 an 89 and a 93 tune all street/performance and i love it. The tranny shifts firmer, it has better shift points and definately has more power. all in all definately more fun to drive and worth the investment. His number is on his site (top right corner) just call him up and he'll help you get what your looking for and what you need to do. ^_^