My first question, you atx, or mtx? If you have an atx, call up superchips. They have killer chips, that redo the shift points (which helps the car immensely) alongside top speed limiter, timing, fuel curves, rev limiter, etc. I had one in my Town Car, and the difference was like night and day. Truthfully it'd be like stepping from a zetec Contour into an SVT. If you live nearby, I'd say head in and do a custom burn. If not, you can contact them, tell them what you've done, and see if they can do a custom burn, or a send you one, let it run for a week, send it back to the, and let them do some tuning like that. Which they do. Had to for my Town Car's speed limiter. Thing topped out at 120 thoough, so *shrug* Oh Well, contact them.
http://www.superchips.com/