Replying to Atomic Theory or Prophet 90s

been looking at these two for a while, they both seem well suited to what i need it for, i just need someone to tell me justifiably, get the ATOMIC THEORY..being an atomic fan.which i have been racing on for the past 5 years.

i ski mainly eastcoast everywhere, sometimes go out west but not often....
i`m 176cm, 20`s, and 150 pounds.
i`m +3 level skier with long racing background, been skiing for 18 years, and want to get into a midfat, something i can carve up everywhere and something i can charge with, as well, the capability to go off piste into some east coast powder...(if it ever happens this year...-_-)
i`m not sure how much each are, but i`m flexible.

i need a ski that can do it all, and i`d like it to be alittle more of a carving ski then park, which i know both are. which ones stiffer?
also what size should i get? i was thinking 177cm for the theory or 179cm for the 90s...am i correct?
or would i be happier on 168cm for theory and 172cm for 90s respectively?

can't demo, as ontario really doesnt have much demo days....
will be mounting with marker griffons.

any advice appreciated!