I do and it is illegal.
I'll switch back to stock when the time comes...

 

Easy to swap out the catalytic & resonator for a midpipe. Both are 1 piece, and removal consists of loosening 4 bolts & o2 sensor. It is one of the better value to hp items. You can get about 6-8 hp from a pipe that you can have a welding shop make for you, or B&B sells for about $200. Definitely make the car louder though. & if you get caught you are in deep do-do. I have the hi-flow cat (w/resonator) on my car.

 

Five bolts last time I counted....

 

Sorry, 5 bolts. But pretty easy to do. Very bolt on. Question is how environmentally friendly are you ? And do you mind going into the shop when you have to get smogged.

 

You cannot use the stock bolts for the end that attaches to the catback. The stock nuts are fine thread and the pipe is not

 

"I have the hi-flow cat (w/resonator) on my car"

me too

 

whats the fine for no cat?

 

It's starts at $700 and UP! Depends on the issuing agency. Impound is a definite possibility. Depends on the officer and if they have an anti-street racing policy in effect. Not to mention you get tagged w/ TEST ONLY for the duration the car is on the street regardless of ownership.
Watch out for the portable smog stations. They are white vans w/ lasers setup on tripods about 12" hi. They test auto emissions as you drive by!