if your running about 5 minute races i would totally recommend 2400's because they are more punch (accelerate faster).
if your running about 8-10 minutes i would recommend 3300's gp's
i like the gp's more then the sanyo's just because they are more punchy. the sanyo's are good for the race if your qualifys are shorter.
i'm planning to run 1500's in the qualifys even if i run out of battery power. just because they accelerate so much faster