1. The lower receiver
2. The bolt assembly
3. The Barrel nut
4. A 1-piece outer barrel.
Lower receiver, top view:
Lower receiver, side view:
Bolt assembly:
1-piece outer barrel:
WA style hopup:
Finally a different barrel nut is required:
So they're still leaning either way on gun vs conversion kit, but it's sounding more like a conversion kit to me because there's already Magpul GBBs in the making as we speak (Example: KWA). It might be better for those guys with the AEG version to have an option to switch. Still, they need your feedback.
It's probably also important to mention that this kit should drop right in, there's no dremel work involved or anything crazy like that. Although Peter did tell us there's a bit of a break-in, the action will get smoother over time with use.