We run spools in the rear and lockers in the front. 4.10s and 33s. Bfg a/ts work really well at 90 percent of the track. We also run truxus sts I run in second with the case in low. Using a McLeod dual disc slipper that starts engaging on its own at around 6000 rpm It’s an adrenaline rush. The faster you can get the sled moving the better off you’ll be. What engine are you running?