Weight against Voltage?

[Gustav]

I've no doubt the 2200s would be quicker but obviously without the runtime.

The theory behind using gp2200s is that it's best to use more of them to reduce amp draw (and gain power obviously) to offset the lower capacity.That's why i think if you could stretch to the 8XL or 9XL it would be more ideal.Basically they're good for gaining alot more power at the same weight whilst maintaining runtime.

You mentioned buying 2(2s2p) lipos,would an 9XL and 20 2200s cost more? I know which i'd choose between 24volts vs. 14.8 volts.

The runtime is my only concern with the 7XL on 18 2200s, a 9XL on 20 2200s would give alot more run time.

So if your'e sticking with the 7XL it's probably better to use the bigger cells if runtime is important,but to answer your question the 2200s would be quicker.