I bought a belt and tensioner at PartsShop and had a local dealer install them and the total cost (p&l) was about 500. The dealer quoted me 700 for the entire job. So 400 is a pretty good deal. I was observing the tech while he worked and the tensioner looked easy if you’ve done a few. Otherwise there are about a million things that can go wrong…I can’t speak to the motor mounts, but would guess that if you buy the parts at PartsShop and have someone install them you’d be a little ahead of strictly dealer costs….
'00 ML320 "Casper"
'92 400E "Stella"