Don't mean to rain on your parade, but 350 is a lot. I understand the really good condition but that would bring it up to about 250. Sponsors selling "decent" condition ones for 150. Add another 100 for a pristine condition. Still doesn't get up to that price.
Good luck finding one aftermarket for 100 with two in and two out, especially in the size that it is. This one mounts to your stock pipes too and hangers def worth more than ur offer in pristine condition