I have had the car for three years now and have been plagued with the problem of exhaust coming in through the rear hatch. I replaced the rubber weather seal on the hatch and took out shims from the latch to make it close tighter. This helped a bit, but I was still getting fumes if I opened the front windows. I have no AC, so in the summer I was always playing musical windows. I finally took it to a muffler shop recommended by a local Mercedes mechanic who they use. They took the tail pipe comming from the muffler and cut it off so it faces to the drivers side instead of straight back. Then they extended it so it is flush with the rear side body. All the exhaust is now blown straight to the side as I drive and doesn't get caught in the back draft behind the car were it was coming in. Many pickup trucks have the exhaust facing sideways because it ends up comming in the back window of the cab.
Why didn't I do this mod sooner?