they do work pretty well with most speakers, eliminates all cancellation from gaps around speakers/ rattles in door panels/ subs pushing back of cone in rear deck setups. but the type x's really should have a 1/2 cubic foot box. i have 2 sets of those speakers, rears have the mdf box and dash speakers are about 1/4 cubic foot. I'm gonna stuff dacron in the front enclosures to fake the bigger box.

i find a lot of midbass is added with the baffles most of the time tho. try mounting baffle first, then speaker ring. test out the sound, then undo the machine screws from the ring and remove speaker. stuff with dacron and repeat. see how they compare.