I'd make sure to get the stock VX manifold and cat...it mounts the cat right on the front of the motor Honda seemed to do this on its FE cars so they must have had good reasoning behind it...you might be lucky and score one on a local care forum since people ditch them for a header...if you have some tools and simple automotive experience you could save some money and install it yourself (
http://cgi.ebay.com/ebaymotors/96-97...spagenameZWDVW) this is similar, I imagne for the $150 your mechanic is just gonna weld in a $30 universal Cat, if you want to go that route just order one from summit and go to an exhaust shop, they would probably charge you $50 or so to weld it into your exhaust...if you could take a picture of your current header, there should be an O2 sensor mounted on it, hopefully the previous owner didn't ditch it...you'd probably have a CEL if they did...GL