they are little gadjets that filter out specific frequencies (SP), so you can filter out treble, or bass, if the treble is filtered out sound stage wont be as affected, but not so sure if it will be that great if your not too sorried about sound satge, dont know a huge amount about them sorry.
Suppose you could fade the sound slightly forward to help if staging does bugger up more than you would accpet. Can you not get an adaptor for them to go into the rear pannels? i undersatand about not wanting to cut them, feel the same way about my car. You could sell them and use the more for some 5.25 coxails/comps for the back i suppose, but 6*9s will be fine in an enlosure, as the only problem is that the air moving in the boot is also moving arounf the underside of the 6*9 and some bass cancelation will occur if 6*9s dont have an enclosure, as well as damaging them.
Sorry about all the waffle, hope it helps
Rorrie