There is no certain order to it...as long as the pulley is one of the last; first upgrades you do to the car. An intake...plugs...t-stat...wires...those REALLY don't add gobs of horsepower, if much of any...its all about the supporting mods and with those...FLOW mods...is where you get your power, well...that and the pulley
Get a gapping tool...and gap them to .055". Done.