Are Ernst mufflers any good?
 

The rear muffler in my 420 sel is shot and I need a new muffler. I saw Ernst, a geman manufacturer, makes a replacement. Has anybody had any experience with this brand?

Also is it really necessary to have a rear muffler?. There is already a centre muffler in the system and I'm wondering what could happen if you take out the rear one other than the car would be a little louder?