An older unrestored car in top condition must be treated as very special since they will become increasingly rare. I have known a few Fiats that are still showroom condition and believe they should be preserved. Anything that is in rougher condition can be a candidate for some level of restoration or modification. Certainly restoration does not seem to hurt the value of a car unless it is something very special like a race car.
Do I like unrestored? Yes, I usually spend a lot of time at a show studying some untouched classic to learn how it was at the time of building. It is amazing what I learn.
Cheers
Ron
I think unrestored cars are the holy grail.
I own several unrestored and original paint (or nearly so) cars: 1937 Ford, 1978 MGB, 1988 Alfa Graduate. and an 1961 MGA with 19K miles. Of these, all but the MGA are cosmetically very nice inside and out. The MGA has some rust and the paint is through to the primer in many spots. While it's an excellent restoration candidate, I think over time it's far better left in the original condition. For the past few years, we've used it as a 3D "originality guide" for customer MGA restorations at Eclectic Motorworks and NAMGAR has asked to use photos from it for concours judging. There are fewer and fewer of these untouched cars out there and I think we'll see people value them in less-than-perfect condition as the hobby matures.
Even if I'm picking a car for a restoration, I always prefer an untouched car to one that's been worked on before. I'd rather have a rusty unrestored car with a lot of worn mechanicals than a previously restored car (often with iffy work done that will need to be undone) that's in better shape.
Regarding value, I'm betting the day will come when unrestored originals even with heavy patina will be worth much more than excellent restorations. That's certainly the case with other types of collectibles.
--Carl
I agree.
My ~'69 MGB~ is essentially "as original". Plenty of patina that I do not intend to "improve". The previous owner had it resprayed (original colour) and some of the rugs have been changed (since it was stored in a non mouse-proof garage for 10+ years) but otherwise, it's all as original....right down to the classy AM-only radio. 
I agree with the value of unrestored cars. it's only original once. I had to search long and hard to find a GTV6 that was all original. I am seeing to the small easily fixed flaws and leaving the rest of the car alone.
If your cars are already nice leave them alone and think twice before repainting yours.
I love the unrestored classic. Here is a favorite I saw at a club event; still had the dealer plaque:
In reply to rconlon:
Both my '65 Mustang and TVR (3161) are unrestored but very nice. The Mustang is far from perfect, but has the original paint, and I'm keeping it that way. The TVR has had a respray sometime in the past, but needs another. I am selling it, or I would do it myself. So to me it depends on the car, the condition, the originality, and value.
