The long version

Every M5 generation follows the same script: buy it new for the badge and the numbers, watch it shed a third of its value within a few years, then hand it to a second owner who wanted the car all along and finally gets it at a discount. This one is already most of the way through that cycle, down from the low-90s to the mid-50s, which is exactly when Bargain Window kicks in. That second-owner crowd tends to actually use it, road trips, daily commutes, the odd track day, because they did not pay the badge tax the first owner did.