Go down to the Forced Induction section and look at the RB20 turbo upgrade section and you will have lots of real world results from a variety of upgrades.
Its not the power but the conditions under which it is used that will determine the need for an oil cooler - ambient temps, how long and hard you are caning it.
If the 2wd to AWD adapter you need is the same as the RB30 one I think I got mine from Hy Tech angine builders in Manukau city for a better price than RIPS - so worth checking out.
http://www.hytechengines.co.nz/
I tooth out sounds like too much. How about getting an adjustable cam gear then you can set the cam belt correctly and play with the adjustment for best results.
The front offset at least looks excessive. They are also far too wide for a stocker and tyres will cost an arm and a leg unless you are planning on some ridiculously stretched tiny tyres.
No - just to be clear Hypergear can highflow your R33 or an R34 (OP6) turbo. The 34 will cost more (unless you have one lying around) as you will have to buy one to get hi-flowed.
Probably because Power FC are cheap these days and if you want to Nistune an R33 you have to find a suitable Z32 ecu and set up the VCT control (if applicable).
Easier all round just to avoid V spec - although i don't know about their relative availability where you are. On the other hand allegedly properly maintained ALSDs are fine (but no one ever seems to maintain them).
If you think you may have fixed the problem try disconnecting the battery for a while and then reconnect and see if the warning lights have gone out. Easy done - worth a try
Stick with stock inlet and exhaust manifolds and spend your money on things that will make your car go faster like a better turbo, ecu, FMIC, etc.
If you really want aftermarket stuff buy quality - I can recommend RIPS and Sinco.