Solo, that conversion looks hoaky as hell....hope it's not your bike. Yeah I knew the four pot wasn't plug and play even with shaving the caliper as the spacing for the mounts are different.
I really am enjoying the 320 disc, it's been fun today hearing the front tire squeal and locking it up. Never could do on the R1150RS. If I could only get the wobble taken care of, still fighting with that, along with a wheel hop, dyan beads didn't fix that. I'll try and get the wheel spin ballanced tomorrow. Gotta fix the wheel hop and wobble. But Not ready for buying a rear shock, cann't affoard it right now.
I've got some calipers coming from an early RT (117mm spacing for the mounting bolts, like the G/S) and will still look closer at the spacing, but I'm thinking even w/ the shallow rotors some spacers will need to be made, then have to make sure the calipers don't hit the spokes. Carrier spacers wouldn't be any big deal to make.