To get the R31 diff into TA22 you need to shorten and move all brackets from TA22 to R31. This will cost me about $800 to do. Stud pattern is the same and they come standard with discs.
The handbrake has to be slightly modified to allow discs.
I am upgrading fronts as well, with pug/hilux/corona conversion, the master cylinder needs to be modified.
I have heard that conflicting reports about the bore of the master cylinder. Some say you should keep the same bore to get the extra pressure on the discs while some say you need to increase bored to allow for greater volume in hydraulic fluid movement. Which is correct????