$127.95 shipped from Amazon.com
I bought 3 of them; one for me, one for another GT buddy and one for the builders who do all of the work on my vehicles. They actually tested one on a Pontiac Grand Prix with a 305 V8 and a completely dead battery. I started my Viper with the car battery disconnected and only this in place!
It's about the size of my Android phone and weighs only 14 ounces. Good for quite a few starts before you need to charge it too! Also charges most devices like phones, computers, tablets etc....
http://antigravitybatteries.com/microstartxp1/
See the video here - this is spectacular! I haven't tried it on the GT yet, and won't until I change my cluster - but I am pretty sure it will start it. If it starts my Viper, it should start the GT easily.
[video=youtube;bf7u8rQTt94]http://www.youtube.com/watch?v=bf7u8rQTt94[/video]