Mercedes cars were never meant to be sports cars (at least the current ones). They are luxury vehicles FIRST, performance second.
BMWs are performance/handling first and foremost. No matter how big an engine you put in a Mercedes, it is still going to play second fiddle to a BMW. Besides, you can get all BMW's (with the exception of the 7-series) with manual transmission. You can't say that for Mercedes cars. Like I said, Mercedes are luxury and comfort first, performance second 😉 All those Renntech's and AMG's are nice, but all come backed with an autoshifter b/c Merc can't make an decent manual to handle all the power and torque...pity 😛