If your head unit is flexible enough, it would be best to use it's crossover's. If not, you can use the crossover's on the amplifier. The benefit is to be able to dial in your system far better then what a passive set of components with a fixed crossover point could. Either way, the adjust ability and control is superior in a properly set up active front stage. I don't remember if there is a write up for going active on here. Might search and see if you find one. If not, we can talk you through it. By going active, you can save money on choosing raw drivers, and using the built in crossover's, because you are not paying for an external passive crossover.