Okay so I searched and can not find the answer so I am posting it. To make a long story short when I lived in Missouri I had a hi-flow cat and muffler both from magnaflow installed. Well now I am in a state where there is no emissions inspection so I am thinking of pulling the cat. What I need to know is will the car still run good, will I get better gas mileage, and will I see a slight gain in performance?

Thanks

99SSEI with CAI, drilled 180 stat, and previously stated exhaust mods.

If you saw a performance increase it would be extremely small. I'm cammed, upgraded SC etc etc and run a 3" cat. At one point I put on headers and was waiting for a cat to come in, the only difference I noticed was how much louder the car was w/o a cat. For the sake of being legal, it'* worth it for me.

I would say just leave it on. Besides chances are you will start throwing SES lights if your car has 2 O2 sensors.

Ive got a 2004 GTP and installed 3" down pipe, no cat,no resonator, 3" piping all the way back and reduced it down just before my stock mufflers. It sounds really good! It will set off SES light,so you need a program to disable. LOVE THE WAY IT SOUNDS,Not too loud, not too raspy and enough to keep my sanity when driving! Before, I ran a 14.26@97.43 mph, after exhaust work, it really dropped down to a 13.98@100.68 mph w/drag radials!! So, in simple terms, YES, you will make more power, drop KR and all the rest, however, I would not recommend it if you plan on keeping it mostly stock! My plan for my GTP is to run Mid-to high 11"*!! Currently I'm 13.18@106.88 with a slippery 60ft@2.0 sec. Im just about maxxed out with bolt-ons! Next up; stage 3 intense heads,60lb. injectors,stage 4 cam,2.8 pulley,intercooler,converter!!!!