40k Skimmer Indy 500 Test Run

A couple days ago my game fell apart due to tornado (Dallas area). After the craziness passed I was sitting around the store and wrangled a couple of guys together to test out the Indy 500 rules I had made a while back. We tested one lap and quickly found out a couple of things. Terrain rolls on 1 and 2 are ridiculous. In the first half of the lap I think we immobilized on terrain a total of five times combined. That's been changed to 1. Overall the flow and balance of the game seemed alright. Nothing seemed overpowered but I really liked  the feel of it. I'm going to try to test it out a couple more times before I try starting a league. One thing I do want to do is have a faction based upgrade Chaos, Imperial etc. If anyone has any suggestions I'd really appreciate it.