I am about ready to bite the bullet and replace the factory speakers and add a amp. I have found a 2 way component 6x9 for the front and 6 1/2 2 way for the rear doors. The speakers are CDT brand and a 75w x4 Eclisp amp. I plan on placing the tweeter on the A pillar. How will this sound without a sub? I listen to rock and alternative. Options anyone?