My 1989 300E's odometer stopped at around 90,000 miles and I get the boucing speedometer although no tampering.
On a 30,000 mile car, I would expect a very clean engine bay. Perhaps it still has the wax on the water pump. Wheels should look brand new, with a high amount of sheen and silver hue. After 90k + X miles on my 300E, you can tell which wheels have been in the front and which ones in the rear. HVAC decals should look new. Underhood stickers shouldnt look new nor destroyed. The interior seat leather shouldnt have a single crack or tear.