In my opinion it would definitely be beneficial, and I think someone like SOLO needs to offer this soon. Their HFC + resonator kit for the 2010 and 2011s was dyno'd at an additional 15 HP over stock.
Have you looked at the tube before the cats? Is there a flange there that could be unbolted, or does the tube go straight to the cat as one piece? You'd think GM would have put a flange there to make changing the cats easier, but maybe not
Anyways, I think this is really the LFX's best chance at getting gains similar to LT headers on the LLT engine. May not be quite the gains, but you guys area already starting out with more power anyways. I'd bet 10 to 15 rwhp with something like a SOLO HFC would be doable.