I need help...

[Kamaro Killer]

I have an 88 GT Hatchback. I used to have a weak system in my car, but it was stolen. The system was put in by the previous owner, and it sounded alright, but with my flowmasters, I need something better than I had. I had two 12" speakers in a ported box with a 400w amp. I don't even remember the brand names, it's been awile. My head unit (I still have it) is a Kenwood and has 45w X 4 (I think ) I need to redo the whole stereo system. Any suggestions? I'll have about $500 to $600 to spend.

I also wanted to know if someone has any ideas on a box I could build to fit some 12's in for my hatchback. I can get dimensions if anyone needs them. Thanks in advance, Keith