I have recently bought two jl 12w1 subs to replace my old pioneers, they are in a sealed box in the hatch of my car being driven by a Alpine mrv-t500 amp. I figure these subs can handle more jam so I want to replace my amp.I'm thinking
the jl e1400d monoblock would have more jam than my current amp for the extra
thump I want. I dont need to double my old amps output but I want more. Any suggestions are appreciated.

 

I think your subs and amp are quite well matched. Making sure you are having proper current flow would be my first step at improving your system. 4 AWG power/ground wire and a good ground are a start and maybe even a stiffening cap depending on what vehicle you have..

If you are stil not happy with the output, I would suggest a ported box as your next step. If you truly do like the sound of a sealed box but need high SPL, you are going to need to replace your subs and amp and spend a fair amount of money.

 

I'd stay away from the cap, but definetely x2 on the ported box and upgrading power wires.