Wow, you took your G82 to a standard, everyday muffler shop? Not going to sugarcoat it, but that's fairly disappointing to see. These cars deserve a proper exhaust such as a single mid-pipe/equal length exhaust. The S58 shouldn't just be neutered. In terms of flow, the stock exhaust is designed to flow in an efficient manner. Deleting a resonator or muffler could offset your flow and give you power loss. It will be negligible, but we see it all the time. Highly recommend a legitimate exhaust from any reputable brand.
