The 33 cost me more to purchase than anything but i looked after it. Spent a bit of money doing little things and replacing parts that were slowly deteriorating due to age as well as the turbos which was a bit of money but other than that i didnt have too much trouble. As well as mods but thats the same with any car.
The r32 was a bit cheaper but due to its age there was a bit more preventative maintanence. Things just get old and need replacing and i always work on the theory that if you own a gtr no matter what sort it is, r32-r33-r34, you should have 5-8 grand in the bank just for those times when something goes wrong and you need new turbos or a rebuild etc
In the end if you find the right car and you want it then buy it but always remember unless there are receipts or you did it yourself, then the engine will need a rebuild sometime and it wont be cheap.