[chr2002ca]

Weight over the rear wheels isn't necessarily a bad thing. Weight can actually be put to good use(Nissan gtr for example). The Optima Red Top weighs 39lbs. Not sure where you got 45lbs from. Yellow top? The Braille is a decent option, but if you're running electric fans and fuel pump, or a big stereo, you might strain your alternator with that battery and it or the battery will end up dead in a year. I agree with on just keeping a Lithium in the front. At 9lbs, you'll use that much weight in good cable to put in the trunk, plus there is the voltage drop due to the distance, although the lithiums are great on voltage. I say buy the heavier, more powerful battery and put in the trunk and use the weight to better balance the car and then sleep easy knowing you'll always have the cranking amps you'll need. Use the extra money you saved over the lithium to buy lightweight components for the front and remove the weight up there. That's my 2 cents.