I just put one in my truck (<450hp model) along w/ the valve body. The one I got is a much lower stall speed (than stock) so the motor doesn't get the opportunity to spin up as high before the t/c starts hooking up.

The truck was a ton faster before..... but now it shifts right, tows killer, gets wayyyyy better mileage around town (running 1100-1250rpm instead of down shifting all the damn time and running 1750-1850)

 

cool deal feels faster but have to bring it up on the converter it is move 9 mph with out any pedal with a 38' gooseneck trailer

 

I would consider doing the valve body.