Well then I'd personally spend it all on a subwoofer. I found a JL Audio W6v2 on Amazon for $289 New (usually $539). I'd also get a vented box for that extra kick.
I don't usually work with price ranges, so someone will have to give an opinion on the other brands like Fosgate, Kicker, Kenwood, etc.
-2004 Mach 1 "Natasha"- JL Audio W6 w/ custom box, 8000K HIDs, Sequential signals, StangHi tune, Borla Stingers with catted X, deck lid & lower valence, C&L intake package, H&R Super Sports
-2001 White Vert V6- Sold