I drive an automatic 91 lx 5.0 convertible, all stock cept dumped 2 chamber flows and a K&N air filter, I want to get some basic mods, like a shift kit and underdrive pullies, I was wondering if anyone knows how much a shiftkit helps you. I was lookin at the TransGo one and they run about 100 bucks and seem t obe good, like how much can it shave off a 1/4 mile? thanks for the help, in advance.