Help with Subwoofer box, whether to port it/what ports to use?

Hey. I'm running Two Alpine 12D2 on an Alpine PDX M12 Amplifier, with the headunit being Alpine CDE113BT

I am currently using 4GWG wire, earth and live

I am about to purchase another PDX M12 Amplifier so both Subs are being run to separate amps (should give me more bass) Once I do get another amp, I am going to upgrade the wiring to 0 gwg, which will put into a distribution block, then split into two 4gwg which will be run into the amps.

Anyhow, I built a custom box for the Subs, size being 34width, 16.5height, and 22depth" with 19mm MDF.

I wanted to know whether I should keep the box sealed or make it ported when I get the second amp, and if I do make it ported, what kind of hertz, and size of port would be best.

I have been watching Youtube vids all morning, and I'm undecided whether I should use an areo port, or, as the box is bigger than Alpine recommended, I always have the space inside to add extra wood pieces to tune the box better.

Basically, all I want from it, is really a good, deep, rich thud coming from the subs, however everywhere I've read it says a ported box is louder and I'm just so confused about what I should do.

Any advice/tips would be much appreciated