IMO, rear mount was a good idea for reducing engine bay heat, but you have fun driving that in the winter or even a little bit of rain........ Extremely hot turbo housing plus cold snow or water in general, you're going to crack/warp the housing. If I were you, i would do the junkyard build up, just not a rear mount. But good luck with it either way.
Edit: That sounds like its most if not all that you're going to need.
03 Evo VIII
535whp @ 33psi e85
428whp @ 24psi 91oct