engine loud from inside
2005 c320 engine loud from inside, normal from outside, no engine miss, exhaust system fine
How did you get inside the engine? It is very noisy inside an engine there are many explosions per crankshaft rotation. It is very much quieter outside of the engine.
Noise levels are very subjective. Loud to one person is quiet to another. If you do not like the interior noise level you can install sound proofing. Check car stereo shops for installation of sound proofing.