i hate how everyone thinks that spk's, dalbellos, and full tilts are th eonly good ski boots for park.
i have the 07/08 nordica supercharger spark, and love them. if they fit your foot correctly, get them. they are a freestyle boot and rip all mountain.
but is the 70/80 flex what you want or need? im 120lbs, and level III skier and theyre perfect. if youre around that, i highly recommend you go back to the shop and buy them.