You need to get the specs of the driver and see if the volume of the box is right, or the port is right etc. (Cmax, Q, etc) If price is your concern, a new driver is the way to go. If performance is your goal, the subs you mention cure all the math and R&D issues you don't get by dropping a sub in a box made for another driver.

It's all ball-bearings these days.

Panny 3000 PJ, 118" Carada, Denon 3300, PS3, Axiom QS8, PSB 5T, B&W sub, levitating speaker wire