You ARE a Pathy God! You have inspired me an will be my mentor (darn near hero!). I will be 4x-ing in the Marble Mountains and Klamath National Forest in Northern CA, and could use some extra ponies to haul my trailer w/gold prospecting equipment through steep mountain passes. I have often wondered about which engine rebuilds/swaps would work. Honestly, I was leaning toward a small block chevy or VG33. The twin turbo interests me, if not for the power, then for one of the reasons you mentioned in the very beginning of this thread, 'the sound'. I am interested in any additional advice or motor swap suggestions you may have. The one fault I find in my visions of grandeur-engine upgrade dream is, this treads mighty close to breaking my K.I.S.S. rule boundary, lol!
I'm not daunted by many machining tasks (dad and i just rebuilt the engine & tranny on our 1968 D-8 14-A cat) but your wiring skills, and transmission combination remedy are truly note worthy. Those projects may be a touch out of my league, but I'd be willing to invest time trying.
Now that you've had it running for a year are there things that you would have (or are going to) change?
One more smiley face to let you know this is a standing ovation.