I bought my 08 E90 in January from a Land Rover Dealership in NY. The thing was a steal 46k for an 08, premium, tech, cold, with 4200 miles on the clock. I haven't looked back.
One way of sort of "checking" if it was "driven like an M3" would be to go in to the M settings and see what the presets were. My previous owner used the Middle setting on EDC and MDM instead of DSC off, so I know he wasn't driving it THAT hard, or he just didn't know how to work the tech.