volume of enclosure versus shape

[2manytoyz]

I am currently building a system for a 2021 mustang convertible. The available space and irregularity of the shape is the issue I am facing. I can manage to get 4.24 Cu ft gross volume for 2 rockford P3D4-12's (have new in box sitting) but to get the enclosure volume the enclosure shape will be quite odd to say the least. I am trying to figure out how this will adversely affect the performance and if I should just go to a sealed enclosure of a more traditional design or not. 

 

Attached are pictures of the drawings and mock up to make the needed volume work. I would appreciate any input from those with more experience than me.