Here is my deal. I took my 03 SL500 for a drive the other day. There a rather loud noise coming from under the car. I took it to my local mechanic and they said it was coming from one of the pre-cats/resonators?
Anyway he said he could straight pipe them and the car would sound better or I could pay $500 for the part. I went with the staightpipe.
The car does sound more mean, or whatever you want to call it, but it doesn't seem as punchy when you step on the gas. It seems to accel smoother and easier, but I am not sure if it is as fast as it use to be??
I guess my question is can I loose horse power or torque by removing these? I have seen a lot of people do it, but don't complain about any loss in power?
There wasn't any noticeable difference when I got my cats removed and straight piped. Very little low end torque might be lost with this mod but it is well worth the sound that you get. Try doing the tranny reset and driving it hard for a few miles.