Uhh, 5 dice are not too hefty. I have 14, but i didn't volunteer to drive the other car for IC reasons.
BTW have you counted all bonuses? Its not too much, but if you drive AR-enhanced, it gives +1 die. Home ground gives you +2 if you have it.
And most importantly, if you drive VR instead AR, you get to use Response instead of Reaction, and all thresholds are at -1.