A tarp or something over the front of the vehicle is very important and often ignored for deep water crossings.Hey A4B
Not that I go out of my way to go through water ( it just buggers up things over time ) but I have recently done Cape York with water over the bonnet a few times in my 4.8. Had no issues at all. I do have a snorkel and was using a car bra on the deep crossings.