the intake would be a better move, the sound is awesome and looks some much better than the stock air box, the intake wont be much more than $200 if that... go for the intake
JB's Automotive here in Edmonton... or I know the Mazda dealers here install them for 170... but im sure you dont have to have them installed... so i will assume that will drop the price a few bucks.
Trust me, these are just as good as any of the others... of course if you want ones that look nicer.. injen looks the nicest...