I've found that these cars need work done that other cars never, ever need.
like the suspension for example, upper/lower arms. none of the other cars i have owned have this sort of work considered as routine maintenence etc.
-of course I'm sure people do change this stuff, but no one I know with any other marque has done any work on arms. -I lie! 2 mercs have. <-out of everybody i know.
or the bushes/ball joints.
the cambelts on the twin spark needs changing every 36k or 3 years, a bit more often than most cars, so thats a small cost to factor in too.
the windscreen washer jets eventually need replacing
sparks not cheap.
and if you get a twinny, check the oil on a regular basis to begin with too.
I have to say I do get upset at the costs of running my car but it is easily the most enjoyable car i've owned, I love everything about it bar the costs!
take a test drive and see how much you enjoy it, but consider the £££ too.