Ive just got to tell this one: On my 63 corvette split window coupe, was being lifted on lift arms Under the plastic seat floor area!! As the crunching sound became louder, I started screaming, stop, stop the lift!! Instead of the frame , the lifting arms were on the plastic floor areas!. If I hadnt stopped them at that point the arms would bave been through the floor and I guarantee I would have never been told! This happened also (when I wasnt there) on my 450sl 1977, the passenger side floor panel showed tear (behind passenger seat) where a lift arm had been improperly placed. I found this out some time later, and of course no recourse, although i go to only this one shop for my service. So what to do? If you hang around you antagonize the help, if you dont, g--d know what they did to your car! Its a problem. However, I suggest that if shop uses (as most do) moveable lift arms, you try for one with the drive on ramps. Good luck to all, Abe G