Treads, control stick, rear cage, and rear underbody minigun - 30th Crimson HISS
Lower portion (raising and lowering platform), interior, stickers, and piece that connects upper half to lower half - POC brown HISS V5
Rest - Retalliation HISS

I like the new Retalliation HISS design with the rear gunner. I just didn't really like the fixed treads though as it makes it look really toyish. Same for the stickers, didn't really like the color of them.

So, with some HISS V5 parts, I managed to make this my ultimate Retalliation HISS. I added some extra firepower in the rear and moded the roll bar in the rear to fit as well.

This is my Cobra MBT with the HISS V5 as support.