i know this has been posted before and know its on my350z in different places

i would just like to give some props to the guys at Odyssey Batteries

they have lightweight racing batteries that you can save a nice little chunk of weight for little $$$$

this racing battery weighs 15 pounds....
http://www.odysseybatteries.com/battery/pc680mjt.htm

it works just as well as the stock battery would, not for use with big car stereos or anything else that requires a lot of power...

im no way affiliated with these guys, they were just cool as hell on the phone when i ordered it...

 

Yep, these batteries are a great way to shed about 25lbs in static weight off the front end. Even though the G/Z have the batteries located in a better place than most cars (towards the middle of the car, not on the nose), there is a still a small handling advantage and fairly significant weight reduction.

One thing for those considering this battery, if you live in a climate that experiences sub 50 degree weather, this isnt the mod for you unless you plan on swapping in your OEM battery when the temps get cold. These batteries aren't designed with strong cold cranking amps therefore they can get pretty weak in cold weather. I have a few friends with these batteries in their cars barely started when it sat for 10 hours in 40 degree weather. If your car sits in a warm garage and spends nearly all of it's time in a rather warm climate, you'll be okay.

There may be additional expenses too with the potential need for different cable mounting nuts/bolts and a different battery tie down.