no you don't need a pulley. i don't have a pulley. my mods are in my sig. the runs with the M5 were all highway runs, from 50+, 60+ and 80+

it's really weird, almost every time the M5 gets this HUGE leap on me at WOT, but i slowly pull about half a car length after that. we never broke the 150 mark, so i suspect maybe he'd get me up that high.....
....then again, a bigger car gets more wind-resistance at high speeds, which may have been my friend. my car is so low to the ground now with the H&R kit, i'm quite sure i've reduced some drag-coefficient!

also, use your manual-mode on your shifter, you get higher revs out of each gear. drop her down into the lowest possible gear and she screams as you wait to drop the hammer