Re: rear wheel drive, can you actually feel the difference?
You have to compare like for like. Because some manufacturers make lousy cars, RWD or not. So, let's say you compare BMW rwd to Audi 4wd, the difference is remarkable.
Obviously at normal street driving, you will not feel any difference of a sporty nature. In this case whats left to differentiate is steering feel. 4wd cars feel distintively "deader". The steering is not as nimble, and you do not feel as much of the road as you can in a rwd. The best test, is to drive a 4wd vs rwd version of the same model. I've sampled a 997 911c2s and a 911c4s back to back. One after another in the same session. Both models provided by Porsche AG at the track. The difference in steering feel is remarkable. The 4wd version feels more numb, the steering response more inert, and you feel less of the road. The car is also more difficult to place at the track. On an absolute scale it is still good. But comparitively, it is inferior.
At the track, you have more fun in a RWD car. Fun is a personally defined description. But some, like me, like adjustability, as well as drive dynamics when turning into an apex, and powering out of a corner. 4wd cars are generally tuned to understeer, and for drivers who get fast times out of an understeery setup, it is good. But for many others, rwd gives you good adjustability. The confident ones can enter a corner faster.
For me, when I go to the track, if I track a 4wd, no matter if its a subaru or an audi, I never have enough fun as compared to any RWD car. In fact, I have no fun at all. Note that we're not talking about timings. Just the fun factor.
For a fwd car, you do get torque steer. At the track, unless it is very well setup and has goodies like an lsd, this problem is always going to interfere with your speed.