Been using the EIG 14s1p pack from this on SB Cruiser since getting it operational again, as the A123 pack is insufficient to run SBC due to some odd behavior in the righthand motor controller of SBC cutting out at too high a voltage (which it didnt' used to).
But anyway, today I did some testing with a freshly-built (out of old cells but used a lot less than the original pack) 14s2p EIG NMC pack, vs the original 14s1p, just a couple of quick runs from 0-20MPH on each one.
Test done with each pack in turn, packed into the toolbox rather than working into the frame like normal (is a PITA). Each started out at 58v. Note that the 14s2p weighs twice the 1p, so the 2p's runs have that added maybe 20-ish pounds. (less than 10% of bike weight, probably around 6-7% total with me on there)
The 14s2p EIG did better than the 14s1p, but is fairly close for this kind of short run at full charge. Probably see much more difference over a work commute, for instance. Took about 3-3.5 seconds 0-20MPH; distance in the street from the corner of my front yard to the side gate start. Run back was the same. Less sag than the other.
The 14s1P EIG took about 4-4.5 seconds, going all the way past the side gate. Run back about the the same, maybe a hair more time and distance.