Zelos 36 Battery Question Noob

[Rtcurtis]

Hello,
I've been lurking the forums for a little while and have learned a great deal already, tons of great information. I have some experience with brushless cars and trucks and I currently have a BJ 29 and an Impulse 31, both are great fun. I just ordered my Zelos 36 and it should be here next week. With the Zelos I realize I need batteries that are 50c or more, my question is why does everyone recommend a 5000 mah battery? There are plenty of Lipos that are 6-8000 mah, why not use these to get more runtime? Thanks for answering the Noob question.
Rick

[fweasel]

weight, size, cost to name a few.

[Erroneous]

The air tunnel under catamaran boats raises the floor much like a center column in a car limiting the capacity/ size of packs you can run. I run 4 5800mah packs in mine with stronger motors etc and can run for about 6 mins if Im not hamering it all the time. 6 mins is a long time, alot can happen (im only comfortable running for about 4mins). My opinion, after 6mins its time for grease, check for cracks, motor/esc condition, motor alignment etc etc. Beat your face on the water at 60mph for ONE min and it will need some tlc.