For e-maxx duty, get the 3200 SHD packs. Read the descriptions and make sure you get the packs that can discharge at 64 amps continuously. They have 2 cell (7.4 volt) and 3 cell(11.1volt) packs listed.
For 11.1 Lipo, you are better off with the 8s motor. I should have the controller any day now. I will put them back in stock the second they arrive (expect them by Wednesday).