I was just thinking about the RUF and I felt like I should give a few tips for going faster to those interested. Stuff that applies at all levels. TL;DR list at the end.
Unlike some types of cars (like open wheel cars with lots of downforce for example) that have very sharp, distinct and fast transitions between brake, turn in, apex, and track out, the RUF needs to be handled very very smoothly and slowly through these transitions. They should blend into one another as much as possible, to the point it may be hard to see where one stops and the other begins.
After the transition from braking to turning for example, there may be a long period where the car is turning at the limit and your pedals are doing nothing (turn 1), but you will have to apply the throttle partially to balance the car before you can apply full throttle as the car straightens out. Other times you will need to get on partial throttle smoothly for a long period of time to keep the car stable (last three corners), and only get on full throttle as the car straightens out fully.
To get the car to smoothly approach the limit you should focus on using the steering wheel as little as possible, and instead control the shifting weight mostly with the pedals.
You have to accept that most of this car's grip comes from the much wider rear tires that carry much more of the load, and those tires will also have a large share in turning the car. (I'm not talking about tire-smoke slides, that's far too much) The slip angles I'm talking about are more than nothing but less than tire-smoke.
Applying the gas smoothly gives you more grip in the rear through those wide tires, (although too "RUF" with the throttle and you'll be sliding), removing throttle or applying brake takes grip away from the rear.
Try to focus on keeping the weight over the rear as much you can and steering with the wheel as little as possible. If you want the car to turn, remove weight from the rear either with the throttle or brake (lift partially, lift fully - smoothly, or brake very lightly and not for very long), keep your steering angles small and allow the car time to move and settle into it's slip angle. It's almost like you are merely suggesting a direction with the steering wheel, and fine-tuning it with your pedals. If you are gentle with your inputs it is far less likely to bite you.
TL;DR, The stuff to focus on:
1. Smooth, slow transitions but as close to the limit as you can
2. Minimize your steering as much as you can, steer with the pedals
3. Keep the weight controlled and over the rear as much as you can (pedals)
4. If you see smoke, you pushed too hard.
Hopefully that makes sense and helps someone, since this thing can be a bit of a handful to say the least.