Just installed the Odyssey PC680 battery. Weight savings total 21lbs. I bought the battery with terminals on ebay for $78 shipped plus $6 worth of aluminum and $9 in Velcro to build the mount. The mount is extremely strong and after going for a drive, my voltage never dipped below 14.1v on the gauge. By the way, make sure your doors are unlocked before you close the hood to your z with the battery unattached... breaking into the z to release the hood latch only took 5 minutes with a long piece of metal wire but still, its a pain in the ***! Attached are some pics:

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