Well what I did was first removed the crippler cap, soldered on a new cat 5 antenna to the pcb in the car (about 6" in length) that helped alot.
Before I did all that I was only getting about 3'-4'(inside), now I'm getting bout 10'-15'(inside). I think one of the other reasons that the range on the Supra's is bad, is cause the antenna on the controller is shorter than any of my other rides.
Then there's the real tricky one, the crip on the pcb in the car, excellent skill required. Check out the link below for images of the mod.
http://www.questformadness.com/ 