In theory, I think that you should be able to take your quad in as deep as you want so long as the snorkel is above water. I don't get machines any deeper than I have to, though, so I don't have any first hand experience with snorkels. Thats more or an eastern US thing. People out here ride in the mountains instead of the mud. The exhaust isn't what you're worried about- it's the intake. You don't want to suck water up into the engine. The intake is where your air filter is, so if you know where that's at you can judge how deep you should be getting your quad.