I didn't get a chance to start swapping the front ends, but I did offer up the new calipers to the xj fork, and I'm happy to say it looks very promising
I'll need to mill a little off of the mounts on the calipers and then make a adapter to get to the upper ear on the caliper. The offset is only off by 2-3mm, they are starting to look like the best 31 dollar ebay purchase ever (yeah I know, the master... I'm just gonna see how the xj one does, and if it isn't up to the job I'll pick up a r6 one later).