I did a bolt in battery kit using a Lithium battery yesterday on my '13 GT500, it dropped 29.5 pounds off the front of the car.
We also had rotors built for the GT500 fronts, prior to 2013's and for the rears that dropped. They are both two piece, aluminum hats, superb quality and made in the USA, lighter than any other replacement rotor out there. Rears on the pre-'13 cars came in at 13 pounds stock and ours were 9.3 each. Fronts are 25 pounds and ours are 20.2 pounds each.
That's 46.5 pounds total for those things. Not a bad start.
is the battery work on dd car?