8 inch subwoofer

Been looking to upgrade my Memphis mojo single 8' and need some recommendations for a dual setup. Anything under $1000 can work and looking for around 1k watts im running it on my RF Punch P1000X1bd and might get a second one if needed.

Hey guys I'm setting up a system for my 97 firebird, I only want to take up the top area of the trunk and leave the bottom spot for the t tops so space is limited, not sure of exact dimensions but I think it's about a 10 inches high and a foot deep and like 40 some inches wide. So for this build...

I am thinking of getting two 8 inch subwoofers and putting them in sealed boxes no bigger than .35 cubic feet per box. Does anybody have any suggestions on what subs I should look at getting? I listen to mostly metal music with fast double bass, so I want the subs to be able to keep up with...