I have a Magnaflow 12259 muffler for sale.
3" openings in a centre/offset layout.
It is currently attached to a Y-into-twin pipe setup for a BMW E30, but is naturally compatible with any exhaust system and is reversible. It has two mounting hooks welded to the body.
There is surface rust on the pipes as you can see; however, the muffler itself is in good condition.
At this stage, it's basically just taking up space in my ski pass, so first $30 or best offer takes it.