This *only* works if the app uses Environment.getExternalStoragePublicDirectory(String) to get the location. At present, it won't redirect private data (stuff in /data/data), I may look into that later.
Apps this works with Chrome... Sorry, that's all I could test with.
Using logcat instead of Xposed to log info (logcat | grep "Downloads2SD").
* Fix security check. Google thinks it needs to enforce internal SD card storage.
* Added restore default buttons.
Added a check to ensure the new destination is viable (e.g. not an unmounted/removed SD card).
Graphical bug. Reboots may or may not be required for changes, but it never hurts to just reboot anyway.