Hey Scotty, my 2000 S500 Merc vibrates pretty badly from 2000-3000 RPM. It does it in any gear and is not speed dependent. It also does it in park so it isn't a problem with driveshaft or tires. I was originally hoping it was just a transmission mount but when checking the vibrations with a listening tool the transmission and torque converter were quiet. I originally thought it was the torque converter but I have changed the fluid a few times and I haven't noticed any difference plus it doesn't vibrate when checking from the bottom. The engine mounts seem fine. It seems to be pointing to the harmonic balancer but I'm planning to take a look at it tomorrow and take the belt off and see if it could be from one of the pulleys. Any thoughts or previous experience? I've seen people have this problem on MB forums but I can't find any answers.