Whatshisface176

I can fit a 5 cu ft enclosure in the trunk, that's the smallest recomended for the 18 BL. I'm just curious if having 2000 watts on the BL will be louder then my set up right now? At the moment i have a hifonics brx 1100.1d pushing the 2 Fosgate P2D2 12s. As for my electrical system, i just have the stock 105 amp alternator, duralast gold battery under the hood, and a kenetik hc600b as my secondary battery. I will be upgrading to a 200 amp alternator and a hifonics brx 2000.1d with 2000 watts to push either the 18 BL fully loaded or the 2 ssd 12s. I'm just stuck on which to choose because i've never heard an Fi sub and am curious which of the 2 subs will give me more output? And yes i have a 99 grand am