2 15's in a WRX for SPL

[Crimson Boom 10+ year member]

I want to be uber loud but not compete, then again, I dont bump as much as I used to. I'd just like to drown out a jackass who decided to pull up next to me blarin they shit

 

[518wrx 10+ year member]

haha, yea i geuss thats what ill do then. what dimensions should i go with for this beast??? and should there be a separating wall in between the 2 subs?? I will have to measure my trunk but i prob want to go as big as possible correct.