The racing comparison isn't very fair to RUF. They just don't have the resources Porsche does to go racing. They attempted it with a couple special edition CTR2s, but as far as LeMans & GT racing go, it's not their game.
Road cars are a different story. RUFs aren't built primarily to beat Porsches, but to build upon the already solid foundation of a Porsche chassis & build the cars so that they are already on their limits.
To put it in a way, Porsche can be seen as the "lion" of the sports car world; they're regarded to as quite possibly, the best performance car ever built (hence the no substitutes catchphrase). The basic 911, for example, solid car. Easy to drive, takes some time & patience to drive fast, & needs to be respected when you're at its limit.
RUF on the other hand, is your "tiger". They are not typically held within' the same regard as a "lion"/Porsche. But, what they are considered to be is a much more
ferocious animal, the RUF a car that shares all the traits of the Porsche, but requires more respect & skill to drive quickly. They are built to be less forgiving than the Porsches & take a large amount of talent to be driven to their very edge (see the video of Stefan driving the Yellowbird).
Because of their "tougher" nature, they lose that driving feeling Porsche is usually so renown for b/c they have mastered the formula in their road cars. RUF throws it away & basically overbuilds the cars' performance. To be blunt, where a Porsche road car is typically set to a 8-10, a RUF is set at 11. You either crank it to 10 or you don't, it's up to you, whilst the RUF is just generally already there; you either learn to drive it as it is, or you don't. It's generally a step too far, but the cars really become something special to drive when you want to see what a Porsche chassis handles like, once the magic formula is gone.
If, that makes any more sense in writing than it did in my head.