ORIGINAL: ChrisW
And I'm told that the Mags can become porous and crack ....
Unfortunately, yes and yes!
I now save mine only for racing! For normal road use, I have a set of MM Cup 1 copies but they are HEAVY!! Some people wonder about me using the mags for racing but I reason that there are far less pot holes on a race track and the kurbs don't (usually) bite. And the weight saving is not only significant but also in the right place - unsprung is worth 10X sprung.
As for values, it seems to me that everybody is asking top money, irrespective of condition. I wouldn't buy a car in less than A1 condition for top money unless there was a special reason. For instance, my car had chips and some evidence of paintwork if you looked very closely and some of the carpet wasn't original. However, all the suspension, brakes, lsd had been refurbed to new condition, the engine was one of the best I have still seen and it drove like a new car.
Since then (2.5 years ago), I have brought the car up to near perfect condition. To me, that was worth it. However, if there had been rust and key parts weren't original, I wouldn't have touched it. Those sorts of car are only worth market price of a good one less the cost of replacing the parts and repair. This is always more than an owner thinks their car is worth. For instance, non original wheels is instantly a £4000 discount!
It has been said so often but when buying a 964RS, patience is your friend!