I posted this on Benzworld, but thought I might get some different opinions here.

I've been getting a weird noise from the driver rear of my car. It starts once I hit 10mph and seems to match the engine speed. If I'm driving 30mph with the gas down, I hear "tick tick tick tick". The more I press the gas, the faster it get and if I release the gas, the sound goes away immediately. When the weather is warmer, it seems quieter and as the car warms up it seems quieter.

Was thinking that something was making contact, but considering the sound goes away when I release the gas, I'm not convinced. Could it be the exhaust?

I noticed this today (see picture). Is there supposed to be some sort of rubber or bolt here? Also, how many rubber exhaust donuts does the 300SD have? I'm only seeing two towards the end of the exhaust pipe.