Great Planes Ammo for Rustler/ E-Firestorm

While waiting MMM, I was thinking that I buy Traxxas Rustler or HPI´s new E-Firestorm. I have already Mamba Max controller and I was wondering whitch motor to go with and then I saw these: http://www3.towerhobbies.com/cgi-bin...o+36&search=Go

I think that price is quite awesome? These are somekind of clearance items? So I want to know is any of these good choise for Rusty/E-Firestorm with MM and 3s Lipo? Maybe Ammo 36-56-2600kv or 36-50-3300kv.