My car was really good in 4wd taking 4th overall. The 20k front diff oil made it very easy to drive, and the 2 other settings I recommend changing for carpet are:
- shorten the front link up-out on the tower
- change the axle height for the thickest shim on top (highest front roll center)

My new Motiv motors and batteries were fantastic. I ran modified with the 6.5 turn and it's butter smooth. The graphene packs are fantastic numbers for spec racing. Just an FYI I did some practice runs in 13.5 4wd and did 17.9 best lap, while with a 6.5 turn I could muster a 17.7. The 13.5 Motiv rips! I can barely beat it with a mod!

Source:

K. Wenger