HW requirements are pretty flexible. I recommend fast storage (nvme/ssd), lots of cores (the more the better) and as much RAM as you can get. If you do the server rack thing, there's a lot of used hw on ebay that will do well (some with 128-256GB RAM). Otherwise, form factor doesn't matter much, get what you can work with. For v4, I have some recent snapshots, but you should be able to sync yourself. There are some bugs that may help prevent that, but reporting them if you hit them will help too.