I'm not sure what the stages are. But, if it helps describe the process, I pulled out the cats and then installed the G56 exhaust.
Other than performance issues as I described above, less heat radiates from the exhaust system. I inadvertently put my hand on the exhaust shield after a drive and I was surprised the shield was not hot.
Hunter
You removed the cats in the g56 pipes before install? You were not shipped a new ECU? Then that would be a Stage 1 with complete headpipes, mufflers and bobbins for mounting. If that correct?
I like the idea of having a new complete set to modify and the oem to put aside for future return to stock config if necessary.
