I'd only try a 3S Life if your electronics are 3S rated. 3S life will be 10.8v when charged (3.6v/cell) as pointed out. Its usually not just a matter of extra cooling, usually there's a weak link like the BEC in the esc that won't tolerate the extra voltage.

LiFes are also heavier than lipos, about 25% more so you're trading down in voltage and increasing weight as opposed to lipo.

The 'danger' of lipo is much overhyped imho.