A123 would give you better performance and are cheaper to get if you salvage a DC9360 Dewalt pack. Pack building isn't that hard. I built 6pcs of 5 cell packs due to balance issues in my truggy from 3 dewalt packs. I charge 10s1p in series on a hyperion 1210i. Charging time is about 30-35 min due to it's 180Watt power limit. It is also able to recharge 12s A123 (which is the limit). With 10s1p you can expect about 2.5Kw bursts which is more than a 11lbs truggy can handle without wheeling (i do calculate with 250W burst per A123 cell. Peaks of 100-120A is about the limit i recorded with my eagletree). I use a Neu 1515/2Y (1100KV). It sure has more than enough power, to handle a heavier savage, which you would often see converted with a Feigao XL, which normally should be less powerfull due to higher inefficiencies.
Latest video of my truggy with 10s1p A123 and Neu 1515. This is with a center Diff. I guess the 3 speed transmission of a savage has no center Diff. So expect more wheelies depending on gearing.
Edit: Adding balancing wires is not absolutely necessary. My oldest packs are still within balance after 80 cicles(without balancing). I made sure that all cells were fully charged before i built the packs. Checking voltage from time with a voltmeter is all i do from time to time. The easiest way to see if your cells are in balance is when you drive and power suddenly falls within seconds.