Thanks for the link to the pistons & rods thread and the instructions on the other FAQ items. it helps a lot. I have some reading to do.
I'm switching to a manual transmission primarily for traction control off road. The van will eventually replace our current camping rig which is a 1980 Toyota Land Cruiser BJ45 Troopy. (3.4L intercooled turbo diesel, dual transfer cases and front/rear air locking diffs) I want the van to have similar go-anywhere capabilities. If it can go 90% of the places we can take the Troopy we'll be happy. We spent 2 months camping in Baja California in the Troopy late last year. We realized that some of the technical driving in the mountain passes near San Evaristo was much easier/safer with manual gearing and a low range transfer case. I'm not saying an automatic couldn't do it, it just would be more difficult to control wheel spin in low traction conditions. The 5th gear OD will be nice since the van already has 4.11 gears in it.
I'm only 50% sure about the turbo at this point. I don't like the potential reduction in overall reliability. The SDS EFI system can go either way (normally aspirated or forced induction). I want EFI for primarily dealing with elevation better than a carb setup. Any performance or fuel economy benefits are secondary considerations for me. I might pull a trailer someday with the van and thought the turbo system would be helpful in that area.
I can't wrap my head around how I would design a slip/expansion joint into a fabricated exhaust manifold for a turbo. (Think of the expansion joint in the Dodge Cummins 5.9 manifolds.) The turbo chokes off the exhaust and traps a ton more heat between the turbine and the exhaust valves. That heat results in a lot more expansion of the exhaust manifold. I'm worried about sheared-off exhaust manifold bolts if I did a simple/compact log style design. That's a long exhaust manifold that's got to grow in some controlled fashion to avoid problems. I haven't taken measurements yet but a rough guesstimate of expansion is 0.2 inches at 1250F EGT. I haven't gotten into studying the engine yet don't know if there's enough room to have slotted holes in the exhaust manifold for the front and rear cylinders.