I just copied my info from Jim Trimmer's post. I've yet to verify the actual vehicle the proposed 155/70-17 spare came from.

One issue: SL's have the same bolt pattern as an SLK BUT use larger diameter lug-bolts than an SLK.

SLK same as Crossfire = 12 x 1.5 (12MM pitch diameter and one thread every 1.5mm (I don't know the bolt length)).

SL has 14 x 1.5 lug bolts (14MM pitch diameter and one thread every 1.5mm (I don't know the bolt length of this one either)).