I had a E320 diesel and that thing had low end grunt like a tank. Many people were surprised when they got jumped by a Benz at a light.
I liked the car overall but that damned electrical issue drove me nuts, and the fact that neither Mercedes nor the dealer seemed to be interested in doing anything other than replacing the same component time after time drove me to my end.
The final kicker for me was when the cps sensor went bad on the highway leaving me stranded, after that no out of warranty german cars for me.
The electrical issues were plenty, alternator was replaced, main battery, secondary battery, etc etc
That thing was a tank tho, my parents hit a deer at 50 mph when the e55 was relatively new and thought they were gonna need a new bumper, they parked it at the hotel overnight and came out to the car have scuff marks near the underside of the bumper, ez $200 paint job and the car looked like nothing happened to it.