The problem with these things is that they consume way too much fuel. A US Gallon is 3.78 liters and costs around $5.39 US dollars or around 5 Euros currently. It was as high as 6 Euros earlier. The cost to operate these cars is just too high - especially if you drove them in Europe at high speeds. This car consumes 16 liters per 100km! In Europe, with the stop and go city driving and the ultra-high-speed free way driving, I wouldn't be surprised if that number approaches 20 liters per 100km! And now that electric cars offer similar acceleration and performance at a fraction of the price with even less maintenance - these dinosaurs just don't make sense anymore.
So, a little bit more about the M113K engine. The M113K that is in the W211 chassis E55 AMG cars is very reliable. It is the engine that is similar to the one in the Mercedes SLR-McLaren. That SLR McLaren has a near identical engine but with a dry sump lubrication system and more forged internals. The big Achilles heel for the SLR McLaren - it ruins the car - is the slow shifting automatic transmission. The SLR McLaren shares the identical transmission as the E55 AMG - the same 5 speed transmission that is in the E55 and the S600/CL600/SL600 V12-engined cars. This 5 speed transmission shifts very slowly and the gear ratios are slightly odd - they're spaced more like an American muscle car than an European sports sedan, the gap between some gears are quite large and the gap between other gears (like 4-5) appear quite small. Compared to the current 9 speed you probably have in your current car, this 5 speed is what will make the car feel a bit dated. The 9 speed transmission also "brightens" even a dull engine - as it just shifts so smoothly that it minimizes the power loss and the power interruption - a 4 cylinder E300 feels cheerful and "bright" with the 9 speed transmission! So... The SLR McLaren, having this transmission really didn't suit the car's character. The slow shifting transmission was out of place for a 2 door sporty car. But this slow-shifting 5 speed transmission was appropriate for a 4 door sedan car.