Dilemma indeed

So now that I have my beautiful murdered out silverado back on the road I started the rabbit hole of audio upgrades. Finally built the box I wanted for my L5 kicker 10in an sounds excellent. . Being I didn't want to lose my entire backseat I only removed 1/3 or smaller search.   Now I'm thinking bout a second 10but the dimensions are so odd BUT the box i built could possibly house a second given that these speakers require less cu ft... should I port or keep sealed