thing i had to replace is my power steering high pressure line. Everything else ive done myself and saved a bunch of money. Thats the biggest thing with the Z's if you can do it yourself DO IT. Dont let nissan screw u with the high labor charges. This site is great and has a bunch of info. Im goin to be puttin in my UD pulley next week sometime. 4k is not that much for a car though. I dont know about gettin a 90+ with that amount of money. Youll have to settle for a high mileage Z (100k+) for that amount of cash and its really hard to find a well conditioned Z with that amount of miles. If you really wanna get a nice car id suggest you check out this car(84-89) . I saw it on ebay...looks nice.