Don't worry about the heat, just don't yank the heatsink off, twist it as you're taking it off. You have to unlock the pins by turning them with a screw driver before you can take it off though. The differential between cores is normal as its two dual core dies on one package, so each die has slightly differently configured temp sensors. If you get the xiggy, get the dark knight edition, as it looks better than the regular one and also comes with a mounting system instead of the push pins on the vanilla.