ok........ the E5300 has a x13 multi, so you should be looking @ 3.0 - 3.5ghz without any other adjustment except the FSB....
though i am hearing this chip has an FSB wall at about 360mhz, some chips stop dead.. others can jump the wall & keep going.
ultimately your gonna be locked to a maximum 400fsb as your 6400 RAM may not clock too well past stock, but with a x13 multi 400fsb will be plenty.
in regards to a cooler, what kind of budget do you have for one..??, do you prefer ''push pins'' or a ''backplate'' (the latter will require mobo removal to install)