I had mine lightened in Freshwater Doug, was an ABF one. Just had the face turned down to knock about 3kg of it.
Tried everywhere on the Island for someone to balance it, but couldn't find anyone.
Stuck it on in the end and didn't notice any vibrations or anything else.
Heard with cast ones it's not essential, but wasn't my own opinion, if I could have easily got it balanced, I would have..