The left (driver's side) window regulator went on my 2000 Boxster. I removed it and thought it was strange that it was marked "R" when it was on the left side. I ordered a new one (Uro brand) and saw that it was marked "L". However, the bolt pattern is a mirror image of the original one, so I can't bolt on the motor. I googled the new part number and it's definitely the left side regulator.
I'm now stuck with a regulator that won't fit and don't know why.
Anybody know what gives?