its ok to say "top performance" but what will you be using the car for? circuit? drag? street only? will influence your choice. and for the budget you've set, GTR34 and a really clean GTR33 s3 are outi'd say you best bet is the r32 gtr and throw a few mods at it. just remember that a car (esp a skyline, and a GTR more so) will NEVER be an investment. you are going to lose a fair bit of your paycheck if you get one. consider the ongoing maintainence costs too. can quickly add up.
imo looks 34>32>33 and performance in choronological order. gl