they're decent subs. if you like them, that is all that matters. i'm sure they will sound great in your explorer. but dont use a bandpass box. that signifigantly narrows the frequency range and diminishes the sound quality.
as far as the subs go: if they sound good, and the price is right, go for it. but i dont know if they'll hit as hard as your rockford subs. you heard them in the store. all speakers and subwoofers sound different in the car. Ask what their return policy is. then you can be sure that you like them. good luck, and keep us informed.