Door speakers with stock head unit

[stogiepuffer]

I want to replace the door speakers in my '99 C-5 and still use the stock head unit. I know I can use 3.5 inchers in place of the twiddlers but what about replacing those door "woofers"? I don't want to add new amps or anything for a while even though that is what is truly required (budget is saving for headers and a few things under the hood) but I would like to clean up the sound some, add a little bass, and keep the cockpit looking stock. I listen mostly to jazz and old time rock loud enough to usually drown out the road noise. Any suggestions? Thanx in advance folks, I appreciate it, Guy