Tried to search around the site, but couldn't find exactly what i was looking for. I live in DeKalb, Illinois . For whatever reason, in this county, we don't have emissions testing. I beleive it has something to do with the amount of farm equiptment etc. Anyway, with this in mind, what can i change out / remove from the car? I know headers, i've seen the posting and the videos about removing the rear cats / baffles etc. Can I completely remove the cats? Both sets? I.e. don't i still need some kind of back pressure for a correct running motor? I've got the car, and the cash, just don't know what I can do without messing it up lol.

 

I've never heard of a LEGAL car without cats. Although I don't recommend it (bc it screws up the environment and you may eventually move) the best way to improve the flow of the exhaust would be to remove all of the cats. Next would be replacing the muffler with one that is straight (if you look at your muffler now, air goes in, makes a 90 degree turn, then exits), you want a straight through design with as little turns as possible.

Do you have a local exhaust shop? They will be able to put your car on a lift and talk with you about different designs. Plus, they most likely will know about the emission laws (or lack there of) in your area.

 

Remember the reprogramming that has to be done or you will get the check engine light as well.

TOXIC

 

You need the cats that are on the headers. They have the o2 sensors right behind them for the engine management. I have headers with sard high flow cats with new SS 2.25" pipeing all the way deleting the 3rd cat with a magnaflow x pipe going straight to the Blitz cans no resonators just custom SS 2.25" pipeing. No lights just extra top end HP. It revs alot quicker but lost some tq. It sounds raw and mean a little like a quattroporte

 

I had the y pipe cut out down to include the resonators, eliminating the 3rd cat and that damn choke point. They welded in a x pipe where the y was and ran straight pipes back to the stock muffler. Sound is alittle louder on start up, vast improvement of sound while driving, and if I really get on it,,ummmm, sweet..
I know if I removed the muffler now it would be too loud.