UPDATE: Drove it through heavy mud, let it sit on it for 2 days.
Took it to drive through car wash today....

a) It's still on despite being blasted a little with the pressure washer in the beginning of the tunnel....
b) It all came clean, with no staining or other marks !!
c) It wiped dry with a rag, no color or anything came off on towel!!
d) It's still dark gray!!


STAY TUNED.................