As some tuning companies does, renaming original cars to it’s own name (Lorinser, Brabus etc) so RUF did in 80s. CTRs BTRs (Groub B turbo RUF) had not only tuned engines, but also lots of other parts replaced (bumpers, exhaust systems, turbos, intercoolers, wheels different air inlets etc.) and it’s own VIN numbers. And of course no Porsche badges 
On the other hand, you can buy a RUF-tuned Porsche for 1/10 of RUF’s price (f.e. 1997 RUF CTR2 Sport cost ~300 000$, when 1997 Porsche 993 RUF – only 40 000$)
A lot of custom work was done on Turbo’s in the 80’s when these cars were wildly expensive and their first owners were willing to go further. Ruf was then and still is today the name synonymous with Porsche specialist vehicles.
This one CTR look 930, found on sale http://www.classiccarstudio.com/vehicle_overview.php?stock_num=1243Â for ~38 000$, is a really nice, clean 930, but not a real RUF production car. 3,3 L turbo with RUF leather interiour, some misunderstandings on door panels, RUF wheels and bumpers.
you can find more at RUF site -
you can find more visiting official RUF site -
For more info visit RUF official site – http://www.rufautocentre.com