This V12 is severely detuned in the S600 however. Rather than the 630 horsepower of the S65 AMG the S600 has exactly 100 horses less at 530. Why? Well, because how else would one justify the price difference between an S600 and S65 AMG for the exact same motor? The average buyer will not know the S600 and S65 share the same AMG engine. A simple ECU tune and the S600 and S65 should be identical in engine output.
Mercedes does make a very significant change in the transmission for the S600. The S63 AMG and S65 AMG both have AMG Speedshift MCT 7-speed transmissions. The S600 gets the 7G-Tronic plug transmission which unlike the MCT uses a torque converter. The MCT replaces the torque converter with wet clutch packs. Why the change? Good question, BenzBoost does not know the answer but speculates it is to protect the S65 AMG performance advantage due to the MCT shift speed giving the S65 a sportier character.
If one wants S65 AMG performance but for far less money, the S600 with an aftermarket tune actually sounds like a value. The S63 AMG is likely the best option of the bunch though saving considerable weight thanks to its M157 V8 and offering a more modern engine design.