I've use Interstate batteries in most of my cars (the S2000 has a Honda one). Very reliable, to the point to never having to think about them for a good 4 years, or more.

Just my 2¢ worth of 5¢. ☺

 

These batteries are good to supplement with a capacitor bank.

 

You have to understand where reviews are going to come from sometimes. So when it comes to OPTIMA and some of the standard batteries... I wouldn't be too concerned with bad ratings. It's an item that is fairly generic, has strict gov't regulations, has some pretty simple, ancient, refined technology in it, is in almost every single car on the road, driven by mostly idiots. When people come in for a new battery, a lot of times they don't even know that the battery is the root cause. And a lot of times, it's not. Batteries can hide a parasitic draw problem, and alternator problem, voltage regulator problem, etc. These people don't know that, then they throw the battery in and it's fine for a while and then a few months later, poof; it's dead again. Then because it was a $100+ item they get all pissed off and probably write bad reviews about them. Plus, there's hundreds of thousands of other customers where theirs' were fine.

 

540CCA in a battery that is less than 5 LBS, I run Shorai battery's in my bikes and if I was looking for a light weight battery that packs a punch this is the one I'd get. You should be able to find it a little cheaper out on the web
http://motowheels.com/i-13058924-sho...36l3-bs12.html

ROD

 

I might be considering this one as my next battery. I really like the Braille Lithium Ion batteries too, but they are quite a bit more expensive, though worth the cost in the long run.

 

I like the new hybrid batteries that use supercapacitors together with lithium cells.
This one for example http://www.getohm.com

 

How long have you been running that battery?

 

This isn't difficult to make on your own for roughly $120 USD.

https://www.youtube.com/watch?v=GUXM1XuLUIs

This guy makes his own with a LiPo battery, a balancing circuit and 6 250mF super capacitors wired in series. It's fine for us, we only have 4 cylinders, but I would never trust something like this on a bigger engine, like a V-8.

 

Yeah I know, I've been thinking of building something like that myself myself.
But it was cheaper and easier to buy a new small AMG battery.
Then I put all the effort in building a new aluminum battery tray instead

 

http://www.ebay.com/itm/6pcs-Farad-C...8AAOSwqv9V6ZV7

http://www.hobbyking.com/hobbyking/s...ePo4_Pack.html

If you frankenstein these two it would actually come out to just ~$100 which is still cheaper than an OEM battery, and weigh in at around 3 lbs.