[Gustav]

A pair of 4s1p in series of decent mah with an efficient motor,can give you 25 mins of runtime.Are you sure you want such long runtimes?Personally i would get bored driving for hours at a time.Also if it's not for long races i wouldn't run any packs in parallel,just get an extra pair of packs(same cost) and change batteries if you want to stay out longer.It'd mean less weight hence less amps, less heat, longer runtimes.Also less breakages due to lower inertia and better handling.

I wouldn't go with a wanderer XL for these kind of runtimes unless you keep the rpms way down(30,000 ish),unless you want to stop to let everything cool down frequently.A Lehner 1950,2240 or 2250 should run cooler for longer.

If you have the money i'd suggest a 1950/10 or 11 turn with a 3695 or 36120 on a pair of 4s1p packs in series and an extra pair of packs(not on the truck ie no cells in parallel) if you want the extra runtime.The higher efficiency of the 8s compared to 6s4p will keep you running cooler for longer and with more power to boot,since you'll be running a big low kv motor.