help this new guy

Current set up Amp: jl jx 1000D (1000w at 2 ohms not 1 ohm stable) Radio: double din alpine touch screen Door speakers: (4) alpine r 6.5 Subwoofer: (help needed) would like 2 12" Budget: 350 will go to 400 if it ups speaker quality I'm looking for 2 12" subs and would like your opinion! I...