when i had the mr2 i was pulled over for loud exhaust, it sucks having to swap it out just for them to check it, but basically you have any cop come out and look at your car, they will have you rev it up to make sure its not loud anymore and then they will sign either the ticket or slip of paper saying its fixed. and your done! atleast thats how it went down when i was ticketed.
if you are just going to pay it, i think its like 75-100 bucks.