youll get the most out of it with a map, but you dont really NEED one, it will still run safe!
are you gonna be putting more mods on after the inlet manifold? if so, get your map done when all mods are on... will save you time and money!
also, try get hold of an RBC, much better gains than the JDM...or you can get an extra chamber that bolts onto the bottom of the JDM inlet manifold! that gives very similar gains to the RBC, plus, you wont need to mess about with inlet pipes, as the RBC changes the angle of the throttle body.