Augment kit mk-8 will be the new top level. Higher level kits are being condensed into it. Keep in mind that us the kits to add the slot to an item, not the augments themselves. Similar mats to top level right now will be used to make the kits at 4.0. Augments will likely have a new tier in 4.0 per data miners, but again using the same top level mats as right now, so I would stock kits and the mats, but wait to craft the augments.