Actually, it makes sense. By adding or subtracting discs, you can manipulate to a small degree the amount of low end torque or high end power attitributed to the catback. With every other system, you get what you get. For example, on raceday, take out all the discs for an open back system for the highest horsepower (some have seen a 10hp difference between running no discs and running 12). The biggest problem created is the level of db's. There are many Supertrapp systems (mufflers) that look every bit like a normal one. You don't have to have that closed back look. Their wavetech series looks like your atypical polished stainless steel exhaust tips found on most imports. The discs are buried within the body of the muffler so the look is quite normal actually. FWIW, I have owned Blitz, Greddy, etc other catbacks on imports in the past but the exhaust muffler that gave me the highest horsepower increases for those specific cars was always the Supertrapp. This is the fourth muffler of theirs I've purchased. For just the short time I ran the car yesterday with mine, it was apparent the car was more responsive and quicker. Had several assembly points been addressed with more attention to detail, I'm sure this thread never would have been posted. Poor placement, wrong assembly, wrong muffler, etc. I should have know better but for some reason, I dropped the ball on the muffler choice and should have purchased either of the two above. Combine the wrong muffler choice with open discs so close to the plastic rear fascia and it makes for bad news. Thank goodness we will soon have a carbon fiber rear or paint to finish rear fascia (single right outlet) made available for a group buy. Details should arrive later this month. It looks much worse than it really is because I had the camera literally on the ground facing upwards. From behind the car or any other natural standing position, you can't see the damage. Even the paint bubbling is hard to see unless you're face is damn near on it. Still, might be a good reason now to buy a different rear bumper assembly to go with the front Amuse lip waiting to be put on.