Should I get some aftermarket thermal grease/past? Or is the stock stuff good enough?
the aftermarket stuff seems cheap enough if it works better
The pre applied material works well enough.
However, I would get a tube of AS-5 or MX-2.
If you have to remount the heat sink, you can't reuse the material.
If you don't get it right the first time, and have to remount you want to have some material on hand.
Go to the arctic silver site for a pictorial tutorial on how to use their products.