I've taken ours through water to the headlamps, with the odd splash over the bonnet, any higher than the headlamps is dodgy because of the ecu and fusebox. We don't have a snorkel but the airbox on the l-series has been moved up and ontop ofvghe engine to give a few extra inches of wading depth. We have extended breathers too and change all the fluids at each service.
Cheers
Blippie