I put in a gearvendors OD last winter , so far I have to say it was well worth it

The shift can be a little abrupt at low rpm, downshift. When the throttle is down and your getting on it the shift is crisp and fast. We'll worth the trade off. My challenger ran 13.3 but never tried the gear vender as I thought one more shift would be slower. The splitter really is not usefull except for overdrive in a hot rod as you could not shift it quick enough to do any good in my opinion. Shift switch is on the dash which is a rocker switch to leave my 727 with or without overdrive ,also has a headlight type dimmer switch on the floor for shifting and that is what I use for fourth gear