i have a superchip - it works great for the tranny. holds longer before shifting, shifts a little faster, definately firmer shifts as well. higher redline never hurts especially with the atx... a superchip i'd say is a must for an atx
minds as well get a tranny cooler as well and maybe even a shift kit from transgo to round out the package. thats how my car is set up and i have no complaints other then it being an atx

hope this helps...