Replying to New vs Old (2012 AR7 vs 2008 Rossi Scratch FS WRS)

Ok so this is a very strange comparison, but I currently have the 2008 Rossi Scratch FS WRS (the white ones with the burn marks) as my park/non-powerday ski. I"m not much of a park skier. I love to do 360s off 15-20 footers and ski switch that's about it. no rails. I mainly use these skis as an all mountain ski on non-powder days.  Love carving, bumps, and just messing around on the mtn and going fast.  My other ski are the volkl gotamas, which i love.

I am thinking of upgrading the skis because the rossi's imo don't carve that well on ice and are kinda noodle like (i realize part of this is due to my lack of carving skills). So my question is, would a new pair of AR7s be better at holding an edge in ice? or are they pretty similar to my rossis?  Are they going to be able to handle bombing down a groomer or something a bit more crusty?

As for my stats i'm a level 3, 150 pounds 5'6", 31 years old (so i'm not crazy into park). And as a side note, my rossi's are 176. Should i get the 171 in the AR7? I'm thinking hte 176 is a bit on the longer end for a guy my size.  I ski at squaw/alpine so there's usually good snow (which my rossis can handle) but i've encountered lots of ice this year.