I used 3 smaller o-rings (mainly because that's what I found in my box lol)
Heres my truck:
other than the o-ring mod, I have a home-made drag link (for now), and I have flipped the rear arms for more wheelbase... had to relocate the camber links and flip the shocks to the front of the tower. I also have an RPM bumper.
DP drag link & gear cover, and MIP super diffs are on the way
We race stock motors but it's plenty fast enough for our track