I just bought these components because I had Infinity reference coaxials in the front of my car, I put the coaxials in the rear and these component woofers in the front. I had to cut a hole to mount the tweeter but I already had that planned the the crossover fit perfect inside my door panel. These are not amped they are just hooked up to the head unit. Since these tweeters can handle up to 35kHz, they produce VERY loud frequencies and make my ears ring for a long time without listening to a complete song. My head unit is set at Sub: 10, Bass: -2, Treble: 7. You cannot go wrong with infinity they have amazing quality and a 3 year warranty.