MSS is 1100 bucks and AST is definitely less. Personally I went with MSS because it was the only option in May of 2021 and I grateful it was. I like them so much that I just moved the same parts over from my RWD to X Drive. This says volumes about the part(s). I do feel the car drives better than my M8 on KW's (again says volumes).
I am not a retailer so my only bias or play is ownership and the MSS is tremendous. The spring rates that lead to the compression and rebound are incredible. I have never tried AST so I can not give an opinion.
I truly have no idea my car is lowered with MSS every single time I drive it. I personally like a slightly lower car than fixed springs offer so MSS works for me and the 600 bucks more or so that I paid. Do I readjust it often, hell no- Ill never adjust it so the HAS part is not reflective in my choices.
In reality the BMW dampers on the G8X are so much better than previous M3/4 iterations so almost any spring will be great unless the spring rates are really low and you get the bounce back!!!
