The M113K responds hugely to a Kleemann pulley, larger throttle body, and tune, with modded wagons reportedly running mid-11s on slicks; but one owner warns a tune can induce major hesitation because the supercharger clutch can't react fast enough. Supporting service like supercharger gear-oil and diff/trans changes is treated as mandatory.
Supercharger tuning caution and popular E55 mods
Mercedes-Benz E55/E63 AMG (W211) · mechanical