Hey mate, ive been learning in my skyline since i was 16 Its a real pain in the arse that you know you are allowed to drive it on your L's but cant on your P's . Ive had my P's since october last year and havent been pulled over once. Guess it just depends how lucky you are and where you live.
Ash for power to weight, no one really follows that. Most the people on this website are P-platers, but as people are saying, insruance might give you a mighty kick in the nuts and send you home when you want to make a claim after an accident though. Be smart about mods. My car is not close to stock and i can recall many times which i was lucky to not stack it.
Oh and have fun in it