There are 2 types of brakes on the JDM GT4 ST165
Early models have mingy single pot Corolla type brakes (and diff locks) and the rest got twin pot calipers (with viscous c/diff) which carried over to the ST185.
Interesting is that the Corolla caliper and the later single pot ST185 AND ST182 caliper use the same pad!
I don't think the 202 brake is a worthwile upgrade for the later type ST165 but if you did you'd have to remove 4mm from the brackets or just swap the entire hub as well.
Only real benefit of your idea would be a large increase in pad area
A better option is the massive twin pot brakes/hubs found on the Lexus ES300, the Camry & Windom V6's use the same disk with single pot calipers btw.
These calipers use a larger footprint mount (same as MR2 turbo)
For all these upgrades you'd need to switch to 15in+ rims
later ST165, early ST185 disk/caliper
ES300 disk/caliper (note the bolt spacing). Camry/Windom V6 uses 1 piston caliper
ST185 Caliper/disk on ST165 hub, the caliper is too far out by a few mm and needs a 290mm disk or ST185 hub
St185 (late) disk/caliper (ex Sergei with Znoelli disk/REd stuff pad)
ST165 (late) vs ST185 (late)/Camry, Windom V6
Early type ST165
ST202 fitted to ST165
It worked well but once again the caliper was spaced a few mm too far out
No difference found in diameter and very little difference in thickness
The red stuff pads I found useless for the road, they had no bite and needed warming 1st. Caused a few bad smells inside the car on cold winter mornings.
The best upgrade I found was switching to a ST185 master cyl, you could use ST205 or Camry V6 but the Camry bottles don't fit ST16x