I agree with Mr Flynn, just be sure you know your own financial position and be sure to have someone that really knows Skylines to check it out for you.
If it is modified assume that anything you can't visually inspect isn't really done. Also be sure to put aside at least 1k as emergency "fix it" money. Skylines are great cars but because they make good power, you should assume it has been abused at some point in its life that will need to be replaced.
Remember most 32, 33, and 34's are at least 10 years old if not more. There will be maintenance items you'll need to take care of. No matter how thoroughly you have the car checked out you are buying a used car so parts are worn.
Be sure to have a compression check done and if possible inspect the turbo to make sure it doesn't have play.
Good luck with it. I bought my skyline several years ago and am lov'n it.