The functions are not the same. The AR6000 is designed for use in parkflyer type airplanes and has a limited range, this should not be used in any plane bigger than a parkflyer. The AR7000 is designed for use in larger RC applications. It has DSM2 in it which means that there are two seperate receivers to help inprove range and reliability. The AR6000 only has one receiver in it, and this could possibly be shielded by the engine, muffler, fuel tank, or other items in the plane. The AR7000 keeps that from happening by placing 2 recievers in the fuselage (and they should be positioned perpendicular to each other and at least 2 inches apart if possible). If one receiver is shielded the other one will be able to pick up the signal. The AR7000 has the range to be used for a glow powered plane such as your alpha. Trust me, spend the extra $50 here.

Ken