Zap,
If you do it, make a thread with info/parts used, etc. There were ppl that did and wanted to lower their 2012-2017 Crosstreks, most of the threads were filled with "difference of opinion" (I'm being nice...) responses. Totally not helpful for people that actually want to go through with lowering their Crosstrek correctly...,...,...meaning not tearing the car up because it's lowered. There is info in the threads, but it's laborious digging through crap posts to find it.
Anyways, I like the lowered Crosstreks and I don't really care what anyone else thinks of it. I wish there were a lot more people that have/want to do it. One of these days (idk when) there's going to be a thread pop up about my lowered Crosstrek and what I did to get it there.
I haven't read up on or know much about the new "global" platform that's now being used, but it may just be a lot easier to do on the 2018+ than it was/is for the people that own 2012-2017s...,...,...more compatibility, etc.
If that's the route you want to go, I say DO IT! Dig around for info, call some places & post up for the community when you do find out what works.
Randall