I have been looking around for my first AR upgrade for my AR-15A2, thinking about getting a collapsible 6-position stock for it. I have been cruising the net looking for the best deal and have found a wide variance in prices. My two choices are the standard 6-pos stock that comes on the DPMS Panther or the DPMS "Pardus" stock. I like the Pardus stock a little better than the other one. MidwayUSA has them listed for $59.00. My first question is: Will a stock like this fit on my Alpha 2? My second question is: Since I already have the rifle, can I buy just the stock or do I have to buy the buttstock kit that has the buffer spring with it?