Thanks RT, you have given me food for thought. The car came with 4  17x8" wheels, one of which needed straightening. They seem to fit on the hub lip ok, but I don't know just how snug that fitting needs to be.
Either way I should probably get a dial gauge and check wheel, rotors and hubs as you suggest.
Last night my son and I pushed and pulled on the front wheels at full lock to see if there was movement in the control arms and they seemed good, but perhaps our method is not great. This morning I heard something rubbing as I pulled up. Sounded like a disc rubbing on a high spot, with or without brakes applied., but definitely in frequency with wheel rotation. 
 thinking, thinking,...... 
 

Better off knocking them all out of the park at once, rather than fixing something, then wearing it away whilst you fix other stuff. Good luck man i've been looking for good sized 16's for a while now, don't come across anything under the 1.5k mark for something nice/fancy. The Stud pattern kills us.

Our Stud pattern is very common.. for skylines/silvias, however most of them only take 17's/18's. If you look up Rota wheels webiste for example, they only start 5x114.3 at 17's. 
 
No, will make the car feels/behave different depending on weight, track increase/decrease and size difference.
 
It is very common to have R32 gtst front, and R32 GTR rear wheels on a sw20. Suits the guards quite well. the front are 6.5, where as the rear are 8's. Some say that you need a wider back track, however it is to each's opinion. Most of the time it's for looks. (not serious enough for performance)

The problem with aftermarket wheels for MR2's is not stud pattern but the need to find a staggered set.
 
The Nissan GTST and GTR 16" have large tapered centers and neither will fit the Toyota hub spiggot, so something needs to be done about that. Someone else on here may know if metal hub rings are available.
 
Apart from centering, the offset/width on the front is important if you want good shake free steering with no tramlining.
The GTST wheels have a 40mm offset that is close to stock (45), so the scrub radius is not changed much, and at 6.5" they are not much wider than stock (6")
 
Also apart from looks, with 16's you need to think about tyre availability.
The fronts are no problem, but the rear choice is limited in a 225/45R16 if you want to retain the stock rolling diameter.
FYI, if you were to use a 225/50R16 on the GTR rear (larger rolling diameter than OEM) with a lowered suspension it will probably rub on bumps, so guard rolling needed.
 
EDIT
I just found a pic of the Nissan GTST/GTR combo  to give you an idea of what they look like. The car has been lowered about 1.5"
 
 
 
 

 I need to replace the bushes in the rear control arms, 1990 SW20 3SGTE.
 In the parts catalogs they are not shown so it appears I have to buy the whole control arm.
 Buying a whole kit seems overkill as well, unless there are other members looking to replace 1 or 2 different bushes ?
 Any suggestions?  Thanks...

TwoDogs
 I need to replace the bushes in the rear control arms, 1990 SW20 3SGTE.
 In the parts catalogs they are not shown so it appears I have to buy the whole control arm.
 Buying a whole kit seems overkill as well, unless there are other members looking to replace 1 or 2 different bushes ?
 Any suggestions?  Thanks...

You can buy the whole poly bush kit out of the USA for about $150. The trick is getting your hands on a press to push out the old ones. Whole job will take about a day. It's a must for any MR2.

@Falcon,
 
 I only just saw your response... might have been a solution but too late now, I have bought the "complete set".
Thanks anyway...