I was able to not pay that price
And any performance above the standard battery is secondary to me. The goal is to shave as much weight as possible from the car (~35 pounds from the front of the car in this case), bonus points if it is from the front or top, double bonus points if it is un-sprung weight.
It would be great if I could shave 500 pounds from the factory weight. The wheels saved 60 pounds, the two piece rotors should be a nice bit as well (20?). My mechanic said the down pipe was lighter than the factory bit, but the bigger intercooler made those two parts a wash. Carbon panels will help considerably (hood and fenders are easy (50?). Doors(100?) and hatch(50?) would be harder). Perhaps swapping the giant motorized glass roof for a fixed polycarbonate panel (love all the light in the cabin, but I can't remember the last time I opened it)-100 pounds?) How about the motorized, heated seats? Ditching the head-unit in favor of a simple amp and my cellphone? The spare and jack have already been replaced with a AAA card and a can of fix-a-flat.
Yes, this could be a long road to madness. But at least I'm starting off slow.