Between the edges of the fenderwell and the wheel tubes, what have you tried using to keep the little rocks and pebbles to a minimum? My local track has gravel pits and it's almost impossible not to carry something along with you. I thought about silicone and smoothing it with a blade. I don't want to use foam as it retains moisture. I did cut out the bottom horizontal lips so rocks couldn't get caught on that little ledge.