Optima battery/Relcating to the trunk

With the cold weather it seems my energizer battery just isn't quite cutting it, the remote start has a hard time turning over when its super cold out so im thinking of buying an optima and relocating to the trunk area. I was wondering if anyone was using one of these batteries and also if anyone has tried re-locating one?And if anyone has some instruction on doing so....I.E : materials, tools, exc.