I'm no expert, but my buddy just added a sub in the rear and changed all the 5x7 to three ways and they sound great. you do know the 500 has 5x7's high in the door and two 8" subs in the door as well? whatever you do don't take the 8's out of the door. my buddy did that and put two 12's in the rear and it sounds like crap. those 8's are a great mid.