I have a hard time stepping away from a conventional lead acid or AGM battery. Anytime a mainstream battery comes out that has higher CCA or high Reserve capacity they don't get smaller or lighter. You're giving up something when you go with a smaller lightweight battery and most of that is going to be reserve capacity. If I were to run one of the little lightweight batteries I would only use it on the track and use a regular battery for the road.

I have seen some of the high $$$ batteries come through our recycle pallets(I manage a battery distributorship) and I have pulled some out and charged them with success. The Lithium motorcycle batteries can throw down some serious power and they charge very fast. However I am curious what caused someone to throw away a $300-400 battery in the first place. Some of the "special high performance" batteries are just motorcycle or wheelchair batteries wrapped up in a fancy label for twice the money. I have seen some stinger brand batteries that are just a 18ah jump box battery that you could by from me for $60 RETAIL.

Race Car Only, lightwieght makes a lot of sense, since you have a street car you have way more to consider. Like starting your car at a gas station in cornville USA when it is 100* outside.

I like my 5 year old yellow top Optima but my car sure does need to lose some weight.