Ansa makes a bolt-on clone of the OE exhaust,which is probably priced lower than Eberspaecher or the dealer. Some say the Ansa quality is not as good as OE. I think it's been mentioned that Eberspaecher is the OE supplier.

The OE system is one piece from the cat outlet, but all the replacement systems (including OE) are two piece with a clamp connection just ahead of the axle.

The system isn't that hard for the DIYer to change because it's all bolt on and goes under the axle. I put an Ansa center section on my car about six years ago, and it's still okay.

Duke