[pothole]

Yeah, the Turbo lump is reputedly much more robust than the basket case that is the M96.

I think it's more a case of GT3s holding their value well than Turbos being uber cheap. The GT3 is an out and out driver's car - pretty much all the hardcore sports models - GT3s, RSs, Club Sports - hold their value better than the core range.

Monumentally rapid though the Turbo is, it's not as involving and therefore not as desirable to the hard core enthusiast. In that context, it's competing for attention with all sorts of models from various manufacturers - AMG Mercs, BMW M, Nissan GTRs cars etc etc. By contrast, people who are interested in an RS or GT3 are more likely to only be interested in that model. Supply and demand.