2018 might change before release, it could still be 6 months before you can take delivery
Also I doubt we will see a 100 mile Volt ev range.
GM has the Bolt and Volt mainly for regulatory compliance, and if EVs or PHEVs go mainstream, I think short range PHEVs will be added to GMs shed with a couple halo vehicles.
Think 15 mile range Malibu hybrid.
My hope was that GM would recognize the appeal of actual gas MPGs and the terror of winter driving the Volt and add the Malibu exhaust gas heat recovery system.
In poor weather even with the gas pig humming I sometimes can't fully clear the windshield of ICE
I think that is more important than a small increase in EV range, though I wouldn't complain