Internal Dual Cell Question

[SuperFly]

I'm convinced that speed/weight distribution/handling make a 2 speed internal dual cell one of the ultimate set-ups.

I've built a couple internal dual cell chassis so far, and both are the kind with the rear wheel wells routed out and the batteries running the long way in the chassis. I've seen some pretty nice internal dual cells with the batteries running horizontally, with the original battery in it's original location and no holes in the rear of the chassis.

My question is mostly to anyone who has done both types or the horizontal battery style if there are any major differences in handling, or just general opinions/discussion of why one method might be better than the other.