[DaWhole9]

Researching what springs to go with to lower my M550i and there are a few fixed options but only one adjustable option MSS. Kinda pricey. I have seen that M5 owners that wasn't a better ride at stock height swap in M550i springs or get the H&R Springs for the M550i for a lowered ride thats not as harsh. I am now seeing alot of Height adjustable systems for the M5, H&R, AST and ST, all have height adjustable suspensions for the F90 M5...can those be used on the M550i? A few places show the ST springs as compatible with the M550i, but not all...Just curious why they may not be compatible...spring rates not designed for the M550i? Maybe there are enough differences in the dampers that not all springs will work physically?