r/cheliman,
The name of the Li Po is HiModel.

Here's some links to some of their batteries:

[link=http://www.himodel.com/electric/HiModel_1800mAh_11.1V_10C_EP_Series_Li-poly_Battery_Pack_w_Balancer.php]10c[/link]

[link=http://www.himodel.com/electric/HiModel_1700mAh_11.1V_12C_Li-poly_Battery_Pack_w_Balancer.php]12C[/link]

I couldn't find the 8C 1800mah li po that I have on their site, but that site gives battery weights so you could get one that's not gonna act like a brick with your Axe CP.

I found mine on Ebay and I think there's some on there now... pretty good prices too!

Go big on mah specs, keep the weight same as or less than the stock Ni-Cad and look at the electrifly's battery's C-rating, dont get a battery with too high of a C-rating(discharge rate). I think you're safe with a 15C, I bought mine (8C, 1800mah, 11.1v) originally for my MiniFuntana and thought i'd give it a try and i'm glad i did! I expect mine to last 20-25 minutes with each charge. I also charge mine kind of slow, .25-.35amp charge rate.