I work in the warranty side of the auto industry. I do see claims denied pretty much daily due to something as simple as a modified air filter. If you have an extended warranty, read your contract inclusions/exclusions regarding modifications. As far as factory warranty, check with your dealer/trusted service advisor. Some of the claim denials are bogus, but the legal language of the contract holds up in courts most of the time. I personally would stay with the OEM setup for dusty trails, however, I had to modify mine with a DIY setup (home depot ABS pipe !) due to relocating my washer bottle (WJ). As far as many other street vehicles, I've ran lots of K&Ns. I like the benefit of buying an air filter one time.
