I have very limited experience with MB but finally saved enough money for me and my wife's dream car!! '99 CLK 430 with 38k miles for about $40k

I test drove 4 cars '00 clk 320 nice but lacks a punch of V-8, 3 '99 CLK 430 and 2 of them sound the same quiet and nice but the third one is the cheapest of bunch sounds loudest. I drove car for good 20 min and drives nice and responsive (brakes might need a change) but sounds louder than previous 2 I had test-drove. It is a private owner selling it and I will definitely consider getting extended warranty on it.
My question is loud sound of the engine indication of something I should be aware of or different car’s just sound the same? He did not make any modifications to the car or exhaust.
Thank you

If it s a loud exhaust sound the very worst it could be is an exhaust leak. If you could get the car on a lift check to see that the car doesn t have any damage or marks under the car maybe indicating he ran over something large enough to damage the exhaust.