A 6.3 for sale that was owned by the king off cool Steve McQueen https://www.hemmings.com/classifieds/dealer/mercedes-benz/300sel/1931505.html
It's been for sale on and off for ever. And it's a 20 foot car at best. The late Art Love found it in a LA car yard in the '80's looking very sad. He wasn't aware of its history at the time.
If you want cool and celebrity in a 6.3 you can't go past David Crosby's old car.
It has a hidden compartment in the console cover under the dash where he would stash his hand gun! There is a knob on the dash to match the hazard flasher switch with a bowden cable to release the catch.
Mike Morris, the M-100 group VP owns it now