The 75' turbo was used for homolagation of the 934.
-main major differences are as follows compared to later turbos
-no 75' turbos came with AC..
-single , simple, early style drivers mirror as already mentioned and
-early style dash board cover
-tires were CN36 215/60 and 235/60x15"
there are a few other very small minor details but the above covers the major ones.
Naturally 75-77 tubos came with 911S alloy calipers,,, rims were 7-8X15 Fuchs.. the 76 turbos had two versions of rear wings,, small grill for no AC and larger grill with AC. Tires varied in 76' between CN36 and P7 low profile.
I have been in the market for a 75' turbo with red plaid interior for years... have studied and viewed a number of them but never layed down the money.. Prices varied between 10k US to 30keuro..
There is no set price for anything,,, it all depends on demand.
You cannot compare this car to an RS,, tip top touring M472's are now in the 400k plus range,, the RS will always be top dog in collecting circles but i still think a 75' turbo is very very cool.
Best Regards, R. Groß