Sorry I can't post pics because the XXX4 has been taken apart but....
When I ran a friend of mines with the GTB/5.5 I put the ESC between the servo and the motor. It fit fine but took a little work to get the wires to route correclty without pushing on the body.
I double side taped the cap ontop of the servo next to the backbone. And, my PT was ontop of the servo as well; to the left (when standing behind the car) of the cap.
I mounted a Novak XXTRA on end, against the backbone, behind the motor with the antennta mount moved rearward. I think I might have used the rear belt cover hole to thread the antenna mount into... I'm not sure. Anyway, I had to modify the antenna mount to get it to work. Once it was done it was sweet though.
Also, I cut the body right above the fan on the ESC. I didn't cut it all of the way off, but cut it so that I could bend up the lexan and make an air scoop out of it. It was bent so that it stuck up maybe 1/4" above the body, had a "flat top", directed the air into the fan and DIDN'T look hack! If I remember the fan wa hitting the body anyway and SOMETHING needed to be done about it, so the scoop not only redirected more air to the fan but made the body clear it as well.
Sorry I don't have pics. But using these notes and your brain you should be able to figure it out.