big miles put on them and almost all via hard driving. (In a recent issue of a UK car mag it a reviewer mentioned that one supercar -- I forget the make -- in which he was getting a high speed test ride had racked up nearly one million miles of testing.)
Might add that Porsche (and other car makers) use South Africa for hot weather testing (among other countries: USA and Spain are a couple of others).
Probably true of other car makers, too, but I read where Porsche has a special relationship with South Africa. Essentially there are areas set aside that are pretty much off limits to the common folk so Porsche can really push the cars hard, at very high speeds in very hot weather on 'real' roads and not just on a race track/closed course.
There is a cold weather testing area up in IIRC Norway which allows Porsche quite a bit of freedom in testing its cars in cold weather.
In both cases the authorities work to exclude the press or just nosy folks from getting too close. The car testing brings in some big money to these areas and they want to protect that, keep the money flowing in.
BTW, usually (always? I think it is the law) those test mule cars are crushed when testing is complete and after they have been gone over/through to spot any problem areas (like chassis/body cracks, etc.).
Sincerely,
MarcW.