I think that the key objective is to keep moisture out from below. Ironically its impossible to keep it out from above!, but at least it ventilates easier.
Although I'm not a big fan of the appearance of the Dinitrol 4941 which the factory now use, there's no doubting its ability to repel moisture. So whatever you chose, make sure that where the floorboards meet the chassis, the water can't get in.
Dave, does the factory apply this black stuff, or is is left to a sub-contractor? Last time I was looking round it seemed that the cars in pdi didn't have any coating.
Jays knows, perhaps!
