Polk Audio DXI650 6-1/2" Coaxial Loudspeakers with Poly-Mica Cones (Pair) - $40 w/ FS

I've seen these in several different builds here on TW. They get good reviews here and on other sites.

Link

 

Think I might have to get a set of these. Will these fit in the rear doors of my truck?

 

Damn, says these don't fit 2003 Tacoma's...

 

These will fit the front and rear doors of a double cab and access cab (or whatever Toyo calls it) with an adapter from ********* or Mr. Marv (if he's still active). More information can be found in the below thread.
http://www.tacomaworld.com/forum/audio-video/3198-diy-basic-speaker-upgrade-2nd-gen-access-cab.html

DblCabMN...just realized you are in a 1st Gen. I think those will fit, but you may want to search to make sure.
This dude has them in his 98 Tacoma...
http://www.tacomaworld.com/forum/1st-gen-builds/169004-98toywheelers-low-budget-build.html

I just looked at *********' website and they do not have a kit for your truck, but that may just mean you don't need one. I'm sure there is info on TW that will help.