Howdy All
I installed a zzperf. 2.5 SS DP with cat about two weeks ago. Took a 200 mile trip with it and my milage seems to have gone up a bit. I did not calculate but know how much fuel this trip takes as it is a regular one.
Before install I was clearing the P0420 regulary. Since new pipe no SES light.
Car seems to have more pep as well. Dont know about backpressure I went with the cat because it seemed like a good idea.
Later
Robert