Thoughts please on upgrading to these air filters on the 550. I've heard good things, but also know that most hype on meaningful horsepower increases with filters like these (which look like the K&N type) is just that - hype - and only measurable at wide-open-throttle. Wide open throttle in a 550 gets you a free 'go to jail' card in short order, so real world driving won't see me with lots of wide open throttle. Anyway, thoughts please, and also a domestic US supplier or two who you've had good experience with. Thanks!