Mopar Perfomance's Turbo Action shift kit. It will not force a downshift to first. That's the main difference I'm aware of between TurboAction and Transgo kits. Also the TA kits are specific to the year(s) of the valve body. With selector in 2nd, it still downshifts, upshifts to 1st as needed. The TA kit has engine braking in all gears.

I've run it both with and w/o the accumulator spring and currently am favoring the softer shift. It's a matter of whether you feel the shift might unexpectedly break the rear loose on a turn (autocross).

I generally run with selector in 2nd except for very small and tight courses. It's easier to be smooth in second. Choice depends on personal driving style, fastest sections of the course, and whether the course leans toward slaloms (momentum) or turns and straights (braking and acceleration).

My choice of gearing also relates to the fact that I'm running a much shorter tire than most of you guys.