IMO skylines should be manual (understand if you have a reason/need) but I would look elsewhere.
Performance orientated jdm cars are best in manual and any auto's should be considerably cheaper**
, as they are not as desirable.
**(although loads of dealers will try and hike up the price because of its name status, but they are not the same as their manual brothers, so just know that and either avoid or negotiate a much better price! and be fully prepared to walk away!!!!!).
RB20's are ok and have potential with lots of $$ put into them, but you might as well get a RB25DET, as any skyline is going to be costly - anything skyline tagged these days just add a few 00 to the price.
As Xtremetofu says you might be able to get a r33 gtst??
if you are set on a R33 skyline's consider these ;
Triple check the strut towers for signs of rust, as they rot from in between the skins and can be hidden easily if you don't know what to look. These will all at some point need fixing - many $$$.
Options for wheels are much better on 5 lug variants - I think the non turbo 33's and R32 non gtrs are 4 lug (another reason to go R33 GTST/R34GTT's)
These cars are modifying magnets, so make sure you know what is/should be present - and what night be missing/need changing - more $$$
Lookup what you might be spending just to service these cars annually - as this may help you decide??
Find someone local that has/had one for some time or get a specialist to advise.
Also a good read might be
Skyline Buyers Guide
by moderator Bigchief
Good luck in your search and welcome to the forum.