100 cells per square inch means less restriction than 200 cells, thus allowing the exhaust gases to flow by with less in the way. The cats do just enough.
Less restriction could allow more of that V8 sound, plus my centre box is non-resonated, which helps that V8 sound all the way through and some to be heard in the cabin. A description versus the stock exhaust may be.... imagine the stock sound amplified 3 times!
In terms of performance a free flowing sports exhaust helps the bhp gains but only by 10-15bhp, which to my mind is not that noticeable, that's what the remap is for. The free flowing exhaust definitely helps get the max from the remap..... as well as liberating the sound that most buy the V8 for.
Definitely no popping, bangs or silly dump valve noises.
Oh, by comparison its quieter than my TVR 4.5 V8 which just has one main cat in the way with the one silencer sleeved to provide a straight through exhaust. Taking the pre-cats out made a very noticeable difference to torque and allowed the motor to spin more freely. Same should apply to the RS, but the turbo's also help!
The RS6 remains family friendly with the sound and fantastic under torque load, addictive even. The main consideration after deciding to free up the exhaust with 100 cell cats, is whether you go resonated or non-resonated. This is a very key decision based on your sound requirement or tolerance.
I've no comparative idea of performance differences between 100 and 200 cells, but if 100 cells are available, why would anyone choose 200 cells which restrict gas flow?
NB: I heard several cat-backs but they just didn't do it for me, so waited and then went for the full system, on the basis that if you are going to do it, then do it!! Always had a remap in mind some day, but fear my license will vanish overnight
The 100 cell cats assist in providing a deeper note from up front and is noticeable if you stand next to the car while its running.
Ebony Black Avant with Black Optics, Silver Leather and Piano Black/ Full Milltek - 100 CPSI cats and non-resonated! TVR for the summer..... and SL55 AMG just for the pose!!