Okay here's the deal, I had my SR 4-2-1 Headers installed w/ a custom 2.25" exhaust and a new cat put in and no resonator the other day and when I got the car back it sounds like S***. Now I am 100%sure that they were runing my car WITHOUT the O2 Sensors in the header or exhaust now with having said that will that cause my car to sound S***y and make it run bad. The other question is if I have my ECU reset which I'm having done on Tuesday, will this hopefully correct my problem??

 

nope, not having the sensors will not make your car sound bad. thatll keep the ECU from adjusting stuff rolleyes.gif

if they didnt put them n, and you have the ECU reset than no... it wont fix it. cause without them the ECU will light itself back up.

as far as sound goes, put a different muffler on it, thatll change your sound. smile.gif

 

Look at the header underneath the car and see if you can see the O2 sensor, it sits on top of the part of the header that connects to the Cat.
The original 02 sensor wire the connects to the exhaust manifold will not reach the new spot on the header, so check to see if the wire is hanging.