If you add anything to your frame AND you have a frame problem, the warranty could POSSIBLY be denied if they (FR or the frame mfg) deemed that the addition contributed to the failure. The chance of you having a frame failure is very slim but it could happen. If it were I, I would opt for the bolted on one, but that's just me. Call FR and ask their opinion of adding a hitch to your unit.
Salem 29RKSS Pushing a GMC Sierra 2500HD!
Gotta go campin!