I haven't heard the 645 v2, but the ribbons are definitly worth hearing. I believe NFR still has a 30-day return policy, so it is pretty safe to try a pair. I have 2 pair of the v1 645s, one stock and the other with modifications, known as the KSU 2 (Kitchen Sink Upgrade) including new x-over and enclosure dampening. There is a Yahoo! Group for Newform that you may want to post questions on also.