HPI parts are excellent for the rs4-3ss except the sway bars. tranny and ball diffs. My NovaRossi RR12L3 ate thru the gears of the (rear )ball diff in 2 seconds!!! Ball diff was still good but the final gear was shredded. I think they are made out of alum or very cheap steel. I just got a heavy duty one-way from HotBodies and I am trying to convert it to a ball diff. Crazy?? Yep but I love modding this car. I think i am addicted. I also asked wolfgang at WPR to make me as solid front diff. When I locked up the front ball diffs, the car pulled thru corners much quicker but had a little more understeer. This should be a good setup for tight parking lot.
What type of track did you race your car at???