Tony,
What type of wheels are you reffering to? When going to the 560 wheel I used the 30mm Offset, which worked fine.
http://www.peachparts.com/shopforum/showthread.php?t=71225&page=1&pp=15&highlight=wheels
"Be careful, the 16 inch 15 hole wheels (newer SL - 129), will not fit the 107 without quite a bit of modification. What you want are 15" diameter and a 7" width. The offset is 25mm...very important. These wheels came on a few other non-SL cars so they are out there. The stamp on the back of the rim will read: 7Jx15H2 ET25."