Originally Posted by LarThaL
Stock mid pipe has secondary cats + a set of resonators. Challenge has no cats but only one set of resonators.
I was referring to simply cutting the stock secondary cats and welding resonators. This would give you a 4 resonator/no secondary cat set-up
I have had all 3 set-ups on my car with oem exhaust mod (similar sound to MPE).
First had oem mod only with factory x-pipe and it sounded awesome. Eventually, I wanted more volume so I cut out the secondary cats and replaced with straight pipes. This produced a noticeable increase in volume but also made the sound very raspy. I drove around like that for 6 months or so before getting tired of the sound. Recently I had resonators welded in where the straight pipes were for a quad resonator and no secondary cat setup. Initially I was disappointed by the reduced volume but the tone is much improved. However, not sure how different it sounds now than when I had the secondary cats in place.