Yeah I think this guy is an HD unit. Definitely hear it engaged at low speed at any temperature just after starting it up.
I'll try that swap then look into the balancer after I get done with the shows and 100 or so miles of driving this week. Luckily like I mentioned, its nothing jaw jarring or intense "harmonics :D" wise. If anything, I want to get it replaced just to have my timing marks lined back up again!