u must feel torn between getting a turbo and sticking with your current car especially being 20 and only having to wait a year to get ur fulls. i love cars so much that i drove a gtst 33 on my green p's and was prepare to accept the consequences (back then green p's were allowed to drive turbos but not allowed to drive cars over 125kw per tonne which the 33 was).
i know i'll get burned for this but if you want a turbo i reckon jsut do it...BUT not in a skyline man. our cars are targeted pretty bad. if i was you and i had 14k i would buy a chaser or a galant. both turbo, 4 door, rare and awesome cars but if your heart is set on a skyline, i suggest you wait.