Well after 800 miles with the new engine I can tell you if you're thinking about this swap, don't do it. The gearing is just wrong for the Adventure and like others have pointed out, changing the sprockets to compensate just isn't possible. You can have your trail gearing or highway gearing, but not both.
I found this out yesterday while doing some single track stuff; 7mph is the slowest I could go with the clutch out, and that was lugging the engine. Downhill was the worst; were you want engine braking you can't have it, unless you can go 7+mph.
Sure I can drop to a 16t front sprocket, but that would raise the RPM on the road even higher. Currently I'm right at 5k rpm @ 75 mph.
And... it's developed a nasty vibration at 5k and above. I'll recheck all the mounts and everything tomorrow, although I'm pretty sure it's not a mount issue.
Plus... I lost 10-20 mpg per tank.