I had the chance to check the rear sway bar and the ride is definitely flatter and overall better. I didn't notice any difference in comfort, apart from the rear wheels being now a bit more dependent. My springs are progressive, but on average give a 35.8N/mm rate front and rear. The stock '+17 suspension has approximately a 30N/mm rate front and rear, so I would say the new rear bar is within specs.
Source:
https://documen.site/download/zf_pdf