For sq if you port, go low. Most stay under 35hz. The lower you tune it the less boomy the subs. My latest setup is 2 10 w7 @ 500 rms 1.6 cubes slot ported to 26 hz. A full rms load would yield 145-146 depending on efficiency of electrical components. 3 sealed would do the same number provided sub rms was fulfilled. A well designed ported box will sound almost as good as a well designed sealed. But the sealed will always be a hair better. Proper mixing with an eq can correct the tuned frequency for flat response and make the ported sound as well though.For ported you need someone to build with a lot of experience to do it right. Almost any monkey can slap together a sealed box with guidance. So definately get a member with experience to build and request a video or be there in person so you can learn. Because box design is as important as sub choice in sq.