I got v. good sound out of two DVC 10" JL's run to my back channel, which on that particular amp was stable, even briged to 1ohm. Really pounded They were in a sealed enclosure and still rocked.

Bandpass... ugh. I'm sorry but bandpass is for people who want annoying boom and don't care about quality sound. If you're OK with what, IMO is junk... go with bandpass.

If not stay with a sealed enclosure. Porting is fine - but really only if it's done right, which quite a few car audio shops honestly can't do.

If you look for a primary pair of coaxials, I have had 3 pair of Memphis spks that all served me well and sounded great.