If anyone's thinking of doing this, I'd highly recommend Thermal Grizzly Kryonaut paste. I got a 10C drop in both average idle and load temps after replacing my MBP's stock paste with it, and significantly better battery life, though I don't have any hard numbers for that. This paste usually wins in benchmarks and it's only outclassed by liquid metal. It's $13 on Amazon for a gram, which was enough to do two laptops and two desktops for me.