your a student, worried about cash but you want to know how to get high 12 passes...lol
if your budgeting id suggest that you not get it unless you can budget for when things start to go wrong as well as petrol prices. the problem with skyline and their owners is when something needs replacing we usually want to replace it with something better which means more money.
its a double edge sword picking a stocker or modified one. modified one will save you on mod costs but may cost you in tunes, petrol and overal reliability cause chances are it may have been thrashed, but that all just depends on how the owner looked after it. as for a stocker, youd catch the mod bug which will cost you money aswell.
usually you get what you pay for, but once in a while you may find a genuine gem for 10k, say someone going back overseas. its a matter of giving the car a complete look over to minimse your risk. do you have money for the 100k service that will sure to come up if its close to it?
ive had my car for 8+yrs and its one of the most reliable cars that i have owned aswell as the most i have poured money into.