There's a conversion bracket available for the regulator on the S4 (Corse Dynamics, I think). It wants the regulator to live where the air/oil separator is, so requires removing it entirely. OK...
However, a little research turned up the the fact that certain race bikes (which have a HUGE CF air/oil separator) make 5-7HP more on the dyno with the increased volume. And that some folks who fitted the K&N mod to the engine breather found it made the motor less crisp and responsive on the butt dyno. So I concluded that if I modify the stock breather at all, it'll be to make the breather fitting on the motor entirely open, and to fit the reed valve to the airbox - effectively increasing the crankcase volume and thereby reducing pressures achieved via compression of under-piston volume. Not because I need more power, but Just Because....
Which didn't leave too many more places. I toyed with the idea of mounting on the footpeg hanger, but it'd be fugly, and although in the airstream, also exposed to the elements. And the PO had already drilled a couple of holes in the plastic seat under-tray for reasons unknown. So I drilled a couple more, situating the Shindengen with enough room to connect/dis-connect the Furukawa connectors if desired, also leaving room to route the cables through the groove in the bottom of the air/oil separator.
I still need to route/zip tie things up so the cables are supported, but you get the idea:
My original cables/connectors weren't burnt, so I settled for cleaning them up with contact cleaner and filling the non-weatherproof connectors with dialectic silicon grease (washing out whatever Triumph provided, as I have no idea what it was or what it was rated for).
I also de-pinned the factory connector on the old regulator's battery cable and the equivalent connector on the Triumph link cable and swapped them over to restore the locking feature. Still gonna zip tie the connector up to keep it tight though...