OEM cranks come with some factory balance holes in the counterweights. It appears that it hasn't had any machine shop related balancing because of the few counterweight holes and the bottom of the rods show no signs of balancing either. I hope the machine shop was observant enough to notice if the replacement balancer/damper matched, but the wrong one could have been on the engine to begin with. Best guess on what to do would be to try a cast crank balancer & flexplate/flywheel. However, the unknown weight change of the TRW pistons would still make it a crap shoot Checking/rebalancing the whole assembly would be the prudent option and would help to see if anything else was done incorrectly.
