For what its worth, mine has the cats and first two baffles removed, the third (rear) is intact and it has a Stealth intake. Otherwise stock pipes. No remapping. The car runs like a cool-headed champ throughout the RPM range and the sound is a deep, pleasing baritone. I've been thrilled with the result and the engine is a happy camper.

'17 M3W:
'08 Ural Gear-Up