I dont know about the xheli ones because I've never ordered from them.
I always got them from nitroplanes. I know the ones from nitroplanes are complete airframes.
Here is the link. http://www.nitroplanes.com/exi-450-r...er-kit-v2.html

They say its the plastic version....but what they mean is that some of the head parts are plastic.
Its identical to the Trex SA version, which has a metal frame, metal head block, plastic mixing arms, and a dual material swashplate (half metal/half plastic).
Their description is confusing when they say plastic version, as its not all plastic.
You can look at the close up pics in the link above to see if its what you are looking for.

With the one from nitroplanes, its already mostly assembled just like the Trex SA.

As for the SE kit....The SE is all metal...no plastic parts. So that would be the difference there.
The PRO CF would probably be a clone of the Trex Pro which is carbon fiber frames, and a slightly different metal head from previous versions.
You probably wont notice a difference in flying either the half plastic/half metal or full metal heads. The difference is just bling in reality.
Maybe just a tad better in durability with the metal ones.


As for the metal heads....
I cant tell any difference between the EXI metal head and the Align metal head. They both fly the same.
The only difference I can see between them is that the anodizing is a little bit lighter on the EXI stuff, where as the Align parts are just a bit darker.
Ive heard of people saying the metal is softer in the EXI head, but Ive not found this to be the case.
I wouldnt hesitate to use the EXI head parts any day of the week.


Funny story....today I pulled out my spare parts bucket, and started browsing through it....
Come to find out, I had almost an entire 450 in spare parts....so I built another 450..LOL All I need is some skids.