[jdk_ii]

Not much.

I investigated this years ago.

Even if there were a hub or Toyota rotor replacement, you'll still
be looking at thin rotors.

To accomplish an upgrade to the MK2 to fit 14" wheels is tough.

You'll need a flat rotor that is at least 1" wide, then make
an adapter to fit the rotor to the existing hub.

Then comes finding a caliper that will support 1". You could
use the stock calipers, and shave the pads, but that will
cut the pad life almost in half.

Toyota is notorious for changing fitment once a new model version is developed.

Retro-fit is definitely not in the Toyota Engineer's design criteria.

 

[jdk_ii]

Note -> Some cars above may only be found in Australia.

But the Ford (mercury) Capri turbo rotors 'should' be a direct bolt up affair.

Definitely, check it out. DBA has some great parts, some which
is difficult to get here in the US.