They don't have one specifically for the SLS, but I suspect the SL may work as well. I don't drive my car enough to warrant a cell holder, but if you're looking for one I highly recommend them. We have them in our other cars and they are rock solid and non-permanent.
This works well in a Lexus SUV I have but you have to flip it upsidedown to get it to work in the SLS because of the radio knob & it doesn't look that great that way. .So it will stay in the SUV. Other Guys with SLSs what do you have?