I received the diagnostic for my check engine light elsewhere and the initial quote I got was $500+, but they were able to take care of it for me for less than $250. I guess there are two ways to replace a catalytic convertor and going with an exhaust/muffler shop is the cheaper way to go. I wasn't able to make it out here for the diagnostic check, but when I called they relayed that they would do the check for free and if it took longer than an hour to figure out...then they would charge a fee. Went here on a Saturday morning when they opened and I was in and out of the shop in less than 1.5 hours =)