if your gonna drop 10k+ into your cars go parts, you'd better be shooting for a helluva lot bigger fish than a mustang gt, @ 20lbs i don't even know what kinda numbers you'd be putting down, but i'd bet that your killing showroom specials like the cobra, the cobra r, the ss, just about any special model honda makes, probally nsx's...

i dunno.. but gt's arn't that great, aim higher, and @ 20lbs i don't think oem axles will hold btw... tranny certainly won't.