I agree with everyone who says get a cheap DH bike. First time I went out was on my Heckler. I survived but came home thinking I would have fun on a bigger longer travel bike, 2nd time I went out was on a Santa Cruz Bullit, rode more or less the same stuff. My pal was on a 224 hand he had a great time, Isurvived but came home thinking for the DH trails out there a DH bike is what you need!
Also it would be heart breaking to spend big money making your Trail – AM bike a bit more DHy only to have it ruined int he alps. Spend the 600ish you would pay for Pikes on a decent 2nd or 3rd hand DH bike and leave your good AM bike as it is! I sold my Bullit and now have a 224 too. Its the right tool for the job!