I've run the exact woofer your running..... I posted a 147.9 on the TL sealed off 2k rms... at 48 htz.
I ran a 4.3 cube box with almost 80 sq inches of port, in a slot port box, and to be honest, it was hard to sit in....
also the issue may be your filters on the amp as well.
I tuned at 32 htz. and It didn't like bass upper in the 60 htz and up. and the real issue is this,
the 2000 rms rating isn't really for a good solid all around music sound. the sub has so much xmax that the sub really needs a good damening factor amp. and Some real power
I only ran the sub on 1000 rms daily. but off good clean power. *(jl 1000/1) daily and when I hooked the amp up to an Atomic 3k. well it was a world of a difference the power of the punch was crazy. it hit hard, and killed the upper range as well. I saw at around 65 htz a full good 3-4 inch excursion. sounded nuts and played like a monster.
I suggest trying something a little beefier than 2krms. It really needs a good 3-3500 depending on port size. I suggest also a good 60+ sq inches of port minimum. if you can get more then do it.
It really needs an efficient port. and the size you have now isn't going to do much no matter the tuning nor the power. just not super great as a ported sub unless you give it enough port.