1600 will work fine, but may run at 1333. You can try setting the speed manually. The 2000 is possible only when you overclock the cpu. Get the cheaper ram, whether it's 1333 or 1600. I recommend corsair, crucial, kingston, or any brand with a manufacturer's lifetime warranty.
Just use the "del" key to enter the bios during the post. You'll have to search the bios sections for the ram settings. But honestly, you don't have to change the settings for the ram to run at 1333. Just use auto or the default settings the board chooses. You won't notice the difference by changing it and this could cause problems.