brushless conversion questions

[rcsammy]

i think aslong as the price is reasonable it will be a MMM

so what sort of packs should i be looking at from here? www.maxamps.com
so far from the info everyone has given i know i need 4/5s atleast 100A continuous
personaly i would like similar performance to a nitro buggy amd runtimes long enough to make a 15 minute final(so around 20 mins to be safe) and at the moment it looks like im going with a MMM

or even better would be if i could buy just one pack(even if it is more expensive) that will last me 3 qualifiers and a final so 30 minutes(35-40 to me safe)

are either of those acheivable with the kind of setup im looking at?