I've been running 4" side exhaust with no problems at all. We did notch front fenders up about 4 1/2 ". The pipes fit very nice between bottom of the door and bottom of the rockers. Have no problems at all with ground clearence. Has not damaged paint, yes it's loud, heat is not an issue, can't say the same about leg burns but that only happens once. Don't have flairs so could'nt tell ya about that. Love the sound and the look!!