I have straight pipe on my car, worst thing ive done too my car. My gas mileage went down, have a check engine light on. My front 02 is showing too much activity and dumping extra fuel in. I recommend replacingnit with a new catalytic converter..I know im switching back too one once I get the funds
Weird.
My gas mileage went UP. No CEL. And my primary o2 sensor was not affected.
Also, no funny smell like most others say they have.