Id put the Dual mass GXP flywheel in there. It wil take the "harmonic" out of the issue as much as it can be. Dont try and screw with the engine balance shafts. They are there to take care of second order vibrations, not correct small imbalances inteh rotating assembly.

This Is why I NEVER change flywheel/damper on a stock motor. They are dynamic finish-balanced at the factory.When we build a motor they are balanced with the new damper and flywheel attached (and stamped for orientation) for this exact reason