How to put your kernel sources into an squash fs image, managed transparently by portage.
Howto adjust your wireless regdb a.k.a regulatory.bin used by crda which defines the radio spectrum your wlan hardware is allowed to use.
Howto put your portage main repository in squashfs image and still be able to update/sync using overlayfs.
Setup courier-imap mail server so it uses perfect forward secrecy.
Howto disable hostapd overlapping channel scanning or better howto force 40 Mhz channels even in dense wlan areas.