Did some thread searches and seems like CEC is not the place to go for ACS springs (see
here). Although I did contact them and they did say that they can get the springs to me, however it will be a 2-3 week lead time as they need to order it from Germany
I also contacted ACS themselves in Irvine, CA. Received a price for the ACS springs for the F10 535i back, but it seemed a bit on the higher side compared to what I've seen members get them for in the past ($450-500).
Posting to ask if you have purchased ACS springs, please reply with where I can find a set!
TIA