I have done the elim on about 6 different 2.6's only 2 of them being NA motors. one of the na motors had a pretty bad vibration, and one of the turbo motors had a pretty bad vibration. Most are not really that noticeable. That being said I have had one fail.... and broke the chain... and that chain is connected to the oil pump.... so yeah I have thoes things! For my motor that was balanced and rebuilt with the BS out its hard to tell it has the BS removed! Basicly from what I can tell is they used the BS so they dont bother to balance the motor lol
So if your going to rebuild the motor remove them and get your assembly blanaced. When the vibration is bad its very annoying, but having had one kill a motor I would always remove them! But like said before if you do matinace on them (replace bearings and chain, plus adjuster when it needs it) Which almost no one does...
On a side note I like the added oil pressure you get with them out.