6x9s

Hey guys,
So I blew the 6x9s in my Cutlass, and it got me thinking... My 6x9s are free air in the trunk of my olds. and I was thinking that when I do the mazda, I'll fiberglass a box behind the seats for 6x9s. So, what is better? Free air or boxed? if I box them in the mazda, what volume should the box be? Also, What brand do you guys prefer? So far I've been leaning towards MTX, since they're cheaper, and I find they sound as good, if not better than the Type R alpines. (ofcourse, futureshop doesnt have any of them amped.)

Id say boxed would sound better. in fact. recalling i had a set out open air. didn't sound to bad. but when they where in a box they seem to have more bass.