Overclocking a macbook is a great way to make an expensive paperweight.
Not really. I've overclocked countless CPUs over the years. The only two that I destroyed were an old Celeron processor that I forgot to put a heatsink on and an Athlon XP-M (may have been an X2, I forget) that I managed to corrode the pins off when I'd failed to create a good seal around the head of my phase change cooling system and condensation from water in the air got in. Even that one worked fine until I unplugged it from the board and several of the pins came out in the process.