Whichever piece extends the shifter handle far enough back for me to reach it with out leaning out of my seat. Comfort should be number one priority, then everything else. I bought a Pro5.0 shifter, and the stock handle is designed for a Fox, so it was pusitioned way too far forward. 3rd and 5th required leaning out of the seat, and on every 1st I'd hit my thumb on the shifter bezel/dash. It sucked, and it's not like I'm some 6 foot 8 driver who likes to gangster lean. I drive upright and I'm 5 foot 10. I ended up getting triax handle for the Pro5.0 base, and that fixed the problem for me.