Mercedes Benz CLK Cabrio 200K Sport Auto - Mercedes benz CLK Cabrio - Ride Quality - GrahamMoore

I recently purchased a 2009 Mercedes Benz CLK Cabrio 200K Sport Auto and I expected the ride to be harder on rough and uneven surfaces than my previous MB C220 Saloon. However, on relatively smooth trunk road surfaces there is a significant rumble type vibration from 50 mph upwards coming through the seat (i.e. chassis via the suspension, not through the steering). I have had the wheels balanced but this has made little difference. Is this a characteristic of the harder sport suspension and if not, any ideas as to what might be causing it?

Mercedes Benz CLK Cabrio 200K Sport Auto - Mercedes benz CLK Cabrio - Ride Quality - gordonbennet

I'd be checking wheelbearings, brakes, prop shaft, gearbox (look at the oil on the dipstick) and diff oil levels to eliminate those, if you don't have one already find yourself a good MB indy workshops.

It could be tyres, unknown budget makes would be more likely IMO.

Possibly exhaust touching the body or suspension.