Here's a pic of an Odyssey lightweight battery in an 05+ GT. Don't know the specifics on it (I snapped the pic at a car show) but looks like you can make out the model # (PC680?) on the battery. Also not sure if that mounting bracket is a one-off or something you can buy ready-made. Just thought I'd put this out there as an option...

 

oo that looks really good. Its only 15.4 lbs too :/

 

Those Odyssey batteries are for motorcycle and seadoo applications if I'm not mistaken. I wouldn't use one in a DD.

 

That's correct. Not good for a DD.

Here's the application chart...
http://www.odysseybatteries.com/battery/pc680.htm

It's ok as a racing battery though...

PC680
Small 680 cranking amp battery with metal jacket and SAE automotive terminals.
Also available without the metal jacket for low temperature applications.
Battery measures 3.11" wide x 7.27" long x 6.67" tall with the metal jacket and weighs 15.4 pounds.

Recognize that the reserve rating is small, so storage time with computer draw can discharge the battery in a few weeks. Ideal for Street Rods up to 5.7 liter V-8. Can be mounted in the glove box flat on its back - only 3 1/8 inch high.

Excellent starting battery where high reserve capacity is not required.
Great lightweight racing battery for shedding extra pounds.
Can be mounted upright or flat.

 

Wow, sounds like the OE Motorcrap battery...

 

I know plenty of guys that use Odyssey batteries for the track, but I would never rely on one in a DD.

 

I will take the extra 30 pounds and have reliable starts. Smarter places to save weight on the car.

 

i agree

 

Yeah like dropping 30 pounds off our gut. Not singling anyone else but if you're overweight that's the first place to start.

 

BUT...

For those that are serious at the track, it wouldn't be too big a deal to swap out your stock hunk-of-lead battery for one of these 15-17 lb ones. And it's easy enough to maintain 12v on the system while swapping to prevent any changes or resetting of the electronics.