Would a set of R31 calipers fit stanza struts?
Dont really have any idea on this area just doing my research before committing to a set of coilovers or just standard stanza struts.
Cheers

Depends which version strut you have. If you have girlock type you can fit 200b ones but same almost. You can.fit sumitomo twin piston ones like IM using or sumi 4 piston ones (like IM planing to fit. These come in a pair suited for vented or non vented rotors, I have non vented rotor ones).
Depends on planned mods but the twin pots are good for my l set up even on hill Climb. The 4 piston may require a master cyl upgrade from stock 11/16 to 13/16 or 7/8 even. I hope they ok with 11/16 to be honest. I like the pedal feel as is.

There's heaps of upgrades check out the brake upgrades in wiki
I'm going rx7 4spots on my stanza/200b struts, some people go r32gtst calipers, some hilux 4spots like mik said, some sumitomo like I also have, there are also 2 types of girlocks that fit just need the right disk/hub combo! There is also a few other options there to

Awesome thanks guys, will read further into tech wiki and see how we go from there! We're looking at building an autocross/rally coupe for very little money but as we all know thats impossible (well at least the old man is trying to keep the budget down hhaha) Its an expensive exercises with cage brakes diff engine etc you guys get it.

take a look at this

should give you a decent idea of what at least i know can be done with them

You can make a lot fit Iv got big ba falcon brakes on my stanza struts

In Australia there are two types of Stanza struts,Japanese Tokiko with a smaller stub axle and Australian made versions had 200B 240K Holden size wheel bearings with the appropriate bigger stub axle these are grey in color standard for easy ID.