Q&A

 Master

That engine uses a timing chain to time the cam and crankshaft sprockets, the balance shaft is driven directly by gear to gear contact and should never go out of time like a n engine that would time the balance shaft with a separate timing belt.I would get a second opinion and hope the imbalance is sometime more simple. With a professional grade scan tool look for misfire counts and anything in Mode 6 that may not yet be severe enough to set a code. May be first get your mechanic to try this.
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