Just got a reply from Zack @ Competitive Cyclist. He also confirms that the V1 levers and derailleurs will work fine with the V3 battery and V3 interface. So I've ordered the parts and tools to make the upgrade easier. Looking forward to getting the clunky V1 battery pack off my down tube and the new features embedded in the V3 firmware, particularly the ability to share gearing info with my Edge 530.