RCU Forums - Shotgun vs Flat

Sorry for the infantile question...but I'll still ask it.

My gf just bought me a rustler vxl but didn't get a battery or anything. So - I dig a lil in the forums and end up finding [link=http://www.rcuniverse.com/forum/m_6991897/anchors_6991897/mpage_1/key_vxl/anchor/tm.htm#6991897]this[/link]. PERFECT! Alas, I head over to maxamps and see two that look decent enough (considering I'm a PT Barnum Special) (the 4700mAh 8.4) but one is a "shotgun" style while the other is a flat hump.

Aside from cell orientation, are there any differences, performance-wise, between the two? They are the same price so ?

I don't plan on doing anything with this rc except bashing...so any other suggestions are always welcome.

ALso, sorry if this is the second (or third, fourth, etc) time this has been asked; but the search/filter for the forum isn't the greatest...and also...the whole barnum thing again...

Thanks!