An oft-repeated mantra of M car owners (and to-be M car owners) is that the M version will hold value better, ostensibly due to enthusiast appeal, lower production numbers, and overall desirability. We consult the data from iSeeCars and find out how much value M cars lose over five years compared to base, non-M counterparts. M3 vs. BMW 3 SeriesThe M3: a cornerstone of the BMW M lineup and institution for driver and machine connectivity. X3 M vs. BMW X3The X3 M is another case where the M version comes out ahead. X5 M vs. BMW X5The X5 M also manages to outperform its more sensible sibling, although not by much.