RUF, is at its heart, a Porsche based production company.
Has anyone here thought to go to the RUF official website?

Here's a good page to show that even RUF themselves recognize that their cars are highly modified Porsches.
http://www.ruf-automobile.de/content.php?seite=seiten/home_de.php&rubrik=&id=&lang=en
Think of RUF like this...
Porsche manufactures Chasis.
RUF builds the chasis into a car using parts of their own.
Even on the main page of the RUF site they call themselves specialist in Conversions.
The issue regarding VIN numbers and whatnot is simply a matter of property changing hands and the actual commercial sale of an object.
Buy a car you get a VIN, buy parts and you don't get one... RUF buys parts and sells them built up as cars. Since they bought parts and not a car a VIN is never designated.
Porsche puts a VIN on their car when it is sold as a built car.
RUF buys the chasis and parts to build and in-turn is not buying a car.
So when you buy a brand-new conversion from RUF it is plated with a RUF VIN since the car was never built as anything but a RUF (and every car must have a VIN).
The car is not a tuned Porsche unless you bring in your built Porsche and have them tune it.
Even so, RUF acknowledges that they build Conversions of Porsches to match RUF specs.
Bottom line:
If RUF produced 100% original cars the models they sell would be marked as RUFs and not RUF conversions.
Look under "Our Models" on the official RUF page... Their models are listed as "our converted models" and nothing else.
RUF Official Website: "Our Models" heading
Here you will get an overview about our converted models.
If you have any questions about conversions for your car, please contact us.