Posting pics of the item that you are trying to sell would help your cause a long way.
Especially since you ceramic coated your tips black. It's not original and therefore people want to see how it is compared to stock. Who buys anything without looking at it?
There a reason why this same exhaust minus the ceramic coated tips was sold in just a few days and it's not that much cheaper compared to new. While yours has created not much interest and has not been sold since June 17. Go figure!
http://www.f30post.com/forums/showthread.php?t=884822 (Sold in a few days)
Best of luck bro.