Duncan's build is inspiring, but he did a lot of work including finding and modding a forklift motor, building his own controller from a kit etc. He's also running without a BMS with a Chevy Volt pack which is risky- you personally would become the BMS, which is fine until you get lazy or something screws up without you noticing. So you can save a lot of money in return for both sweat and risk. But the big DC motor gives you serious grunt for the dollar, if grunt is what you really want.