Can you clarify on what you mean by undermount vs side mount? If you're referring to mounting it behind the front wheel between the frame downtubes, at the lower part of the front of the engine, you'll have plenty of ground clearance. My 2015 is lowered and the factory cooller presents no clearance issues. If you're thinking under the bike somewhere, I think you'll be asking for issues. Not only ground clearance, but road debris. Sure, they're all susceptible to road debris, but when mounted in the factory location, it's somewhat shielded by the fender and wheel, but still able to get cooler airflow to it.
Famous Last Words: "Watch Me!"
2015 Denim Black RG, FM ss ceramic coated 2-1-2 pipe, White Bros Original E Series Mufflers, FM ac, PV Tuner