Why do you think they've added the turbo + power/weight restriction for P platers? Because they believe that young drivers just don't have the experience to handle the power. Yes, you might say its easy and all to handle a GTR, but how long have you been driving for?
As we all know, most young drivers thinks they invincible and can do/handle anything, I was the same when I was younger as well. But the truth is, they aren't. So that's why I said NA skylines are a good stepping stone. But honestly, they are pretty quick, of course not as quick as a turbo, but they can out power most NA 6's thats out there.