So I'm looking for new wheels for my 91' sw20, im looking to go as wide as 10" on the rears and front, slightly skinner than the rears. Right now I have the stock wheels on, as my car is completely stock.
I was set on these rotas but then I realized the stud pattern was only a 4 stud (rotawheels.com.au/wheels/kyusha)
I'm really just looking for wide wheels, preferably a smaller diameter but I wouldnt mind going bigger as long as it would fit and not touch the suspension, looking for a deeper dish so closer to a - offset if possible. I dont mind it sticking out of the guards as I have flares in case. 
I dont really know much about tire sizing but i am looking for a bit of stretch.
If you guys know or have anything like this, let us know ! 
Cheers
 

I am also looking at these rotas ( rotawheels.com.au/wheels/rota-p45r2 )
Would I be able to fit the 18x10 +12 on rears and 18x9.5 +12 on the front?
I still would like some tire stretch and so what tire size ?

Try this site when looking at wheel sizes: http://mr2.gordaen.com/wt_calc.php
 
Unfortunately I have no experience with rims that will fit flush with flares, hopefully someone else can help out.

I'm running SSR SP1 18x10 +37 on my rears with 265/35 tyres, lowered on coilovers. Fitment is flush (per my avatar pic).
 
An 10"+12 is going to stick out like dogs balls, so you'll probably turn your car into a bit of a cop magnet.
 
If you really want to go down the rota path, I can price you up a set.
 

I'd suggest a much smaller width for your fronts as there isn't anywhere near as much room to work with as the rears. You'd need a +50 offset to even come close to flush with 9.5 inch wheels and you'd be 30mm into the suspension, so the flares would be a must!
 
Up until last week I was running 225/35 on 18inch rims, 7.5 width and +35 offset. This setup rubbed the inside of the wheel well at full lock and scrubbed under hard cornering and was generally just a pain in the ass. With KW coilovers the clearance is so tight that I can't run any camber at all without camber plates (need to get that sorted haha), so if you think you'll go down the coilover route in the future bear in mind that wide fronts will make it alot harder!
 
I've got a 91 too, do you have power steering? Now that I'm on 215/35 I can tell you the car feels much nicer to drive! I only went smaller to get rid of the scrub but was genuinely surprised by how much better the car feels now.