The power to weight laws were introduced months before i got mu p's many years ago, I obeyed them and managed to drive cars that were faster than the typical illegal cars (like 6cyl cortinas and v8 commodores), without any undue problems from the police. If you drive a turbo skyline on your P's you are asking for it.
A naturally aspirated skyline is plenty fast for an inexperienced probationary driver, and shows maturity in accepting this fact.
Don't get me wrong, I deal with many probationary drivers and share their enthusiasm in the world of high performance cars, but this is real life not NFS.
At the end of the day some police will know enough to book you for power to weight and some will not, on the other hand some cops will see 'Turbo' and dick you anyway.
This has been a community service announcement brought to you by some old intoxicated tool that is taking a break from modifying his turbo skyline in his garage!!!!! :D