I am not sure if you are looking for a combo of all mountain and powder or you already have a powder ski from the way you asked the ?. I have skied both and I am a big Volkl fan ,I own the 06/07 racetiger SL and the 06/07 Allstars. The ac 40 is a good carver with a decent sidecut most likley would be ok to 12" of powder and would be pretty good in the chop the Mantra could go deeper and be better in the crud and cut up pow .For Whistler I would go with the Mantra due to the heavier snow or I would go fatter. I actually demoed the Dynastar Mytic Rider(172cm) with a 88cm mid and liked it much better than the AC 40 which might be great compramize between the 2 skis and the ski I liked better than the mantra and even the gotama was the Nordica enforcer (this ski rocked)177cm (135-98-125) this ski can carve on the hard pack as will float and would definetly fit the bill for the areas your sking. Check them out if you can.