Here's the tenative plan.
Drive the XF until 2022.
Wait until they get the "bugs" worked out of this new engine design.
Watch "Opposed Piston Opposed Cylinder Engine" Video at Engineering TV
Send my car to the "RU-TAZ" engine swap Specialist "Skunkworks" (that now employs about 100 people).
Tell the Service director (Mr. Beaner) that I knew the owners of "RU-TAZ" back when they were just getting started, (and slip him the secret XF handshake for my discount). And maybe a few bucks while I'm at it.