If you are going to but one of these cars, it is very important to do your homework.
These cars, although based on fairly primitive engineering but well proven, are complicated pieces of engineering.
I am surprised that any one would buy a Rolls or Bentley without doing some serious homework on its history. When coming to sell the car, you will realise how important a good history file is.
The 1987 to 1992 Turbo R's are the best to buy, as the later models tend to suffer a bit with electrical problems.
Your choice of colour is an important one too, as resale prices are far better for green or blue cars with light interiors than any others.
Once you have experienced the drive quality and the unstressed way you always arrive at your destination, you will have no other car.
The cost of running them cannot be an issue when you always arrive with a smile, and always look forward to the next trip.
Be very carefully when presented with what appears to be plenty of history. This can be of value, but should never be treated as a substitute for a thorough inspection. Even then, there will be areas that cannot be inspected, so you will need a contingency fund of at least £4-5,000.
You cannot just buy and drive these cars. You have to treat them as an expensive hobby/project. 2 years in and I have spent £11,000 in repairs, and haven't even touched the bodywork. Look out for crow's feet, especially on the roof, and these things all rot around the wheel arches.
A set of tyres alone will cost you £1,500, so a later model with 17" wheels will save you money, and with the shorter grille will look better. Having said that, a pre-1990 without auto-ride will save you a fortune on shocks/dampers/ecu-related problems. Use your ears. If it rumbles avoid it. Use your nose as well - if it smells inside (and so many do) there is probably water ingress (often through failed seals around the screen(s)).
Be careful about colour, too. I particularly dislike green and red. BUT don't be tempted by your preferred colour if you have any reservations about other aspects of the car.