Look, let me say this: The P-plater laws have been around for years and have been tightened up in the last 2. Do your research and you'll find out all the information about these laws.
However, in general, if I was on my P's, I'd avoid doing anything to the car that would attract attention, i.e. adding wings, a big bodykit etc as to the average cop, if your car LOOKS FAST, it probably is and therefore you become a TARGET.
It's like driving around if a BULL'S EYE on the back of your car. I hope this answers your question. Up to you if you want to attract more attention for a Skyline as bad as it is already.