I had a shift kit (Trans-go) in my truck. I experienced light throttle hard shifting and rapid shifts with it. It wouldn't shift back into 1st unless I came to a complete stop. I then switched to a valve body assembly - mines from DTT but I'm sure the others are good too. Down shifts to 1st at 17mph. No more heavy smoke when rolling through a stop sign. Shifts are firm but not a hard bang as with the shift kit. I'm sure you could get the same overall effect from a shift kit, but it takes a lot of time dropping the pan and adjusting pressures/springs, etc... The cost of the transmission fluid with each pan drop adds up :-laf After feeling both the shift kit and VB in my truck, I should have just gone straight to the new VB.