I would say look at the car on its owns merits i.e. visual inspection, service records test drive etc. Almost all the major mechanicals (ie blown turbo's and melted internals) discussed on this forum result from cars that have been modded. A standard UK spec car is capable of high mileages one often quoted car has done 300K on its original turbo's + another was sold on by a member with 147K.
My experience of my car (93 UK) is that parts of the car are showing their age i.e. intercooler, PAS cooler and diff cooler. I'm not sure how the degardation of these parts would have been improved by a lower mileage, after all I brought mine with 79K on the clock which is only approx 8.5k a year and these parts need replacing.
What i'm basically saying is the buying of a low mileage car will not necessarily guarantee you lower future service/repair bills than a medium / high miler.