@jhautz: lol, doesn't everyone think about things like this?
@GD: Wow, yeah, my car battery is getting very weak these last few chilly mornings and was thinking about getting a new one for my Mazda 3. I'd appreciate any info you can get at that price! My g/f already got a new battery so it's too late for her.
I've used a yellow-top Optima for one of my previous cars and they work very well. They are lighter than a regular battery, but not as light as a 4s11p A123 pack. Defintely cheaper though! I liked their acid-free design and the pulse discharge characteristics... good for high-powered audio systems.