for what its worth, could barely tell the difference after installing a lightweight battery that dropped close to 20lbs. Then again this was for hpde and not autoX, where I imagine its effects might be more noticeable.
With rear torsion beam bushing, I had the solid DNA installed around the same time I had miester coilovers and softer 5/3 rates, so hard to account for what did what, but I dont get the sense the car is any more twitchy on hpde course. The rear is a lot more planted for sure.
Only real con I can think of with DNA torsion beam bushing is cost at $300ish. Powerflex polyunI think is around $90