David L linked to their SL65 earlier. Quite apart from the Marmite interior, I buy my cars to drive, and it's £26k; way too expensive for the increase in performance over a stock SL55K, let alone a tuned one.
I think that you need to drive something with the 6 liter AMG V12. My SL55 has super car performance. My CL65 is a ballistic missile.