I think I have about six thousand miles on the engine now. I am currently in Montana. I just drove up through Utah on Highway 89 and then up through Wyoming and the Tetons and Yellowstone and then the Beartooth Highway. I have been blown away with the engine and transmission. It has worked flawlessly. Passing any other vehicle at 8000 or 10000 ft on a mountain pass on a 2 lane highway is trivial.
That said, I agree with the other posters about emissions issues. Mine was a complete engine with all US market emissions components including the EGR. Metric Motors sells both long blocks and complete engines. For the long blocks, you are supposed to move over your emissions components. My first reaction was that they expected you to swap over your intake manifold and EGR and whatever else is needed on your 612 to get the emissions components swapped over. It sounds like, as everyone has said, they sold you a euro or Australian version, as that is what their supplier was able to obtain, but I would expect they would supply some caveat that even though yours came with an ECM you should use your original ECM and EGR, etc. Whether you actually do so is up to you and whether you think you can skirt the emissions laws in your situation. Resale value will certainly be affected if you don't swap over the emissions parts, as the van will not be able to to be registered in many states.
Although most of the vocal forum members are firm believers in maintaining emissions compliance (as it is, after all, a violation of federal law, no matter what state you live in, to do otherwise), there are a couple of forum members that would love to pull the tune out of that Euro ECM now that gde is shut down.
Edit: I'd also suggest you NOT post the name of the shop doing the install, as they are the ones breaking the law. I am certain there are forum members that would immediately report the shop to the relevant Washington state authorities. Good luck and I hope your new engine works out for you - mine has been fantastic so far.
2nd edit: I bought a used JDM engine about 10 years ago from one of the many importers and they explicitly stated everything except the long block had to be swapped from the old engine (exhaust, intake manifolds, etc,etc). Inspecting the engine, I found the only actual difference was one hole on the intake, and so I figured it was easier to just add the hole to the new intake. However, my factory Honda engine is still going with over 350,000 miles and the JDM engine is still under my workbench in the garage. The point being, as Midwest drifter pointed out, the installer, not the importer is responsible for emissions compliance.