The cat on my 380sl was plugged because of a valve stem seal issue. So I temporarily replaced it with a straight pipe, just to see what the effect would be, at least until I can get the seals done. Voila! The car is now far more responsive than it ever was, and I'd venture to say that it has 15-20% more power than before. However, removing the cat made the car noticeably louder.
I only drive the car occasionally, and it's registered as a classic, which doesn't have to pass emissions inspections. So I was thinking about replacing the cat with a second muffler to hopefully muffle the sound without robbing the car of its newly found power, as I suspect a cat probably would.
I was therefore wondering what the pros and cons of doing this would be, ideally without getting into a long discussion of the associated environmental issues.Thanks very much is advance for any advice anyone can give me on this.