I wonder if there will be more going on weapons-wise than just the gun upgrade? Cool that it's more heavily armored, but otherwise you've simply traded a couple of already pretty effective cannons for a couple more effective cannons. I'm presuming this is going to be a situation-specific fighter (to combat heavy shielding, etc)? The guns don't seem to move independently or anything.
I wonder if the "normal" half and cockpit has the skeleton of a regular TIE, with the new armor simply tacked on (an article I remember years ago about "reactive armor" for Israeli tanks comes to mind).
I know, we'll find out; just thinking out loud. Always cool to get new ships and ponder the reasoning and logistics as to "why"!