I am still semi new and a little late to game with car audio. I just listened to a pair of Level 4 18'S, and now I am kind of sold on this brand. I was looking at getting a pair of the level 3 12's or 1 level 4 12 or a pair of Re Audio Sex 12's. I'm using a Hifonics HFI 1500D, but I may later upgrade to something else. I'm working on a limited budget, and any opinions would greatly appreciated.