Deja Vu... I feel your pain, same thing happened to mine over the winter.... the 6000's were/are complete utter trash.
Look into the Hyperion Swift Classic 4000 packs, Mike sells them-
http://www.rc-monster.com/proddetail.php?prod=HP-SW0001 The 80 amp rating looks unimpressive- do not be afraid. All you need to do is clip the Tamiya connector off and use a high current connector, they only have those so they will work with the older cars.
They will make your MA packs seem like toys, they will toss my 14+ pound rig around for 18- 20 minutes and come out lukewarm. The price is also a tremendous bargain- these packs are twice what I expected- I am sold on Hyperion for the foreseeable future- seriously I won't even look at Flightpower anymore because these 4000s are that much stronger than my 2S FP Evo25 4900s were- I sold those.
Look at the Hyperions- they are phenomenal!