Do you mean a 1/10 scale rally car? I'm be looking at the maxamps 3S 5Ah packs or the similar packs from Kokam and flightpower. With lipo, it's not a bad idea to have more battery than you need, rather than push what you have to the ragged edge.
I agree, you are better off spending a little more for something that will most likely last longer, and perform better, and be more reliable all around.
“The modern astrophysical concept that ascribes the sun’s energy to thermonuclear reactions deep in the solar interior is contradicted by nearly every observable aspect of the sun.” —Ralph E. Juergens