Lots of hydraulic suspension parts needed replacement over the last 10 years. Latest was front height corrector (£160+VAT), due to a leak. Now needs a rear height corrector (about the same cost again).
Alternator needed replacement 2 years ago.
Lots of silly little electrical problems. E.g. dirty contacts caused cooling fan to stop working; rear wiper stopped working some time ago, still investigating.
Since I bought the car the engine has been misfiring at exactly 2200 rpm, running fine at every other speed. Number 2 spark plug gets carbon-fouled 2000 miles after replacing.
Drinks 2 gallons of oil between services!
Very comfortable and luxurious for the price, and very good performance too.
The insurance group is quite low for such a high-performance luxury car. But the running costs due to hydraulic system repairs and oil consumption put a slight dampener (I now use a cheaper oil which is also thicker, and therefore less of it gets burnt.)
If you buy the height corrector from an independent company, it won't cost over £60...
In general, try to avoid Citroen dealers as much as possible... Get a Haynes manual, and do the maintenance yourself!!!
Many garages 'forget' to change the LHM fluid. This causes all kinds of problems later on.