I'm unhappy with the lack of bass in my Sebring.  My old 'Venge just had a 50W headunit and that had enough bump for me.  Thing is my Sebring has factory 4 disk changer so I don't want to replace that and I DON'T want a sub.  Is there another way to get a little more bump without resorting to a sub or large amp?

The mids in a decent component set will give you what you need.

I got Alpine Type X  5.25's.. love them...  But I'm sure you don't want to spend that much on speakers.