mah and runtime for racing 1/8 Buggy?

[starscream]

That sounds like a fairly large track so your runtime will be significantly less than a smaller track. You'll most likely have to test your buggy with the 4350mah 5s pack to see how long you can run before it dumps.
I agree with CC, 5000Ah may get you through 15 minutes on a short track but you'll most likely need at least 6Ah for a large track.

Keep us updated as I am very interested in your results.

Thanks

BTW
What kind of buggies are you guys running?