I was wondering whether the cls63 wheel from 2011 fit a 2003 sl55? wiring and core? Thank you for your input.

The gear selectors are different and would require retrofitting. I would assume that none of the other wiring would be directly compatable either.

This however is a speculation as I have no direct experience with the new steering wheels.

Thank you for your input. i can live with that but does anyone know whether the back of the wheel will fit. I previously purchased an SLS Mercedes steering and that did not work, as the back was completely different and too shallow.

it might fit on the car but all the wiring and switches would not work, and probibly all of your sl55 features would quit, you should have your sl55 wheel modified to something you like by DCT