I compete with my Mystique in IASCA comps.
Your speakers are 6x8's.Pioneer makes a good three way speaker which fits directly. If you really want good sound from there you need to wire in an amp by bypassing factory amp behind glovebox. You could also put a component set up front with the tweeter mounted on the doors just in front and below the air vents.Or install one in the rear doors with tweeter balanced up front.