That's a nice looking bike & exhaust.
You're letting it go for a steal compared to retail. It's a little vague, but I think you're selling the pictured M4 and you purchased a new replacement? Or is it the new one that's pictured and the used one that needs polishing?
Anyway, I hope you find a buyer. You might also want to edit your post with what you originally paid for the system. That might help show what a bargain you're letting the old one go for.
It looks like you take good care of your bike.