i would go the 15.. i have one 4 the past year and ive had no problems with it watsoever, even if i did, it is still under new car warrenty (as are most AUS spec 15s)
before that i had an 1992 mr2 turbo and while its not exactly a 32GTR, i couldnt live with it as a daily driver, shit was breaking all da time and spend half its time in the garage...not to mention all da trouble getting parts etc...
in saying that, each car does have its pros and cons...
the biggest factor is do u want RWD drift or 4WD grip???
becoz they are pretty different cars....