I'm not aware of a performance difference but I've been mostly riding with only the default "electronic clutch" setting rather than the two higher settings actuated with the button control. There is a decent boost with only electronic clutch and I don't even have to pedal at low speed with that setting. 16g wire has over 1.5x the cross sectional area as 18g and depending where I mount the battery I can use a cable 1/3 the length of the 24" Qiroll cable. So I guess resistance should be proportionally less. Soldering 16g wire on the tiny MD30 connectors is tedious but doable. The connectors might be the main cause for resistance, I don't know. I haven't kept track of mileage vs residual battery voltage. A voltage monitor could be wired on the power cable easily enough using positap connectors to splice in but I'm not currently inclined even though I have one in a parts bin.
I still want to use this bike on the Palouse to Cascades rail to trail path but I buggered my knee hiking some steep trails in the Columbia River gorge and currently walking with a cane so I'm not sure how that will go.