Just replaced my 1987 GXL's exhaust with a RB true dual setup and now I'm looking to sell my cats for a few extra bucks. One guy offered my $90 for both precats and the main cat. I can't find a serial code anywhere so it's hard for me to get a good idea of what it's worth. Anyone know?

 

About $25 each at the scrapyard. New ones on Rockauto range from about $100 for the cheapest main to $192 for a pre-cat set. Not sure what used ones are worth but he's offered more than you'll get at the scrapyard.