I can run pretty consistent laps with my buggy. It was understeering a fair bit and I changed the diff oils under the advice of people on RCU. It did make a difference. I was not sure how to classify my track but after seeing some pics of other peoples tracks I would say it is bumpy, probably one of the bumpier tracks I have seen. I would like my car to handle the jumps and bumps better. I guess I'll just read the web sites again and experiment with a few things.