There is only one Redpower for 1.4.6 and that is Redpower 2 the newest and freshest version of Redpower. I guess it isn't clear enough in the mod list. But RedPower 2 is also known as RP2 or just Redpower.
So to make it clear. Redpower 2 is in the Mindcrack Mod Pack as well as the DireWolf20 Mod Pack.