I chose to go with ACS springs on my adaptive dampers (335i xDrive). I'm also about to install 437M replica wheels (tires are getting mounted in a few days). I was against the adaptive dampers when I was car hunting, but got such a good deal on a CPO that had it, so I went with it. Turns out, it rides pretty good and I liked it more than I thought it would. Sure it is a bit float in comfort, but very controlled/firm if not downright harsh in sport sometimes. I figure the ACS would be a mild enough spring rate increase and drop that it won't blow out the dampers super fast. Once they get too loose say around 80k+ miles (at 40k currently) I might pick up KW Street Comfort. I had KW V1's on an E92 335i xDrive for 3 years and liked them. Just wasn't willing to plunk down the money currently.
After putting on the ACS springs I noticed basically no change in ride comfort, I honestly can't tell. I mean it still floats on the big bumps on the highway and still very firm in sport. It just isn't a big enough difference to jump out and say, "hey I changed my suspension". However, it's very noticeable visually. Granted I didn't get the sweet look of the aggressively lowered H&R springs or coils, but it looks more like a factory RWD car. If you want to ballpark the gap difference, before I could stick 5 fingers (fist) between my tire and front fender. Now I can only fit about 3 fingers in the gap.
This was as close of a photo angle as I could find/match with a few month prior photo I had on my phone. The actual drop was about 5/8" front and 3/8" rear or 16mm and 10mm respectively. ACS advertises 20-25mm F/R for their 335i xDrive SKU and reduced lowering 5-15mm for "M-Technik" cars. Not sure if they mean M-Adaptive or M-Sport RWD suspension cars. Would be odd for them to list that on an xDrive spring SKU though It's still eons better than before.
And below is a couple other after photos after a nice coat of wax.
