Iv run a few different shorties and nothing I have tried comes close to my Fantom shorties (based off the revtech packs). Buy directly from Fantom.. they are actually cheaper than revtech labeled packs. At 4500mah, you get a nice pile of mah in the shorty.... they maintain voltage EXTREMELY well.
Here is the strange part. I was worried that the high MAH of the Fantom shorty would make it still a bit too heavy (I have a specific weight goal for the fatty RB6)... But I weighed my Fantom 4500 shorty against my 1.5 year old losi excelorin shorty which is a 3800, and my Fantom pack is ONE gram heavier. Figure that one out
I have two of these...worth every penny:
http://www.fantomracing.com/proddeta...?prod=FAN26192