I'd read on other forums that upgrading the tweeters alone provided a lot of bang for the buck and they were right. I just installed them and the difference is significant. It's almost like an entirely new system was installed (minus a sub). They go a long way towards fixing the muddiness of the stock speakers. I highly recommend the upgrade.
I didn't take photos because the upgrade is something easy enough for anyone to do.
1. Remove dash grilles - insert a thin piece of plastic (those store discount cards that you have on your keyrings are perfect - credit cards are a bit thick) around one of the corners and pop it up. Then all you have to do is lift up and the entier piece will pop off easily.
2. Remove the two screws securing the speakers. You will want a very short phillips screwdriver. It may not look like you have enough room but the mounting area flexes and you can push it down a bit. Even so my tiny screwdriver was in contact with the windshield the entire time.
3. Use a screwdriver to depress the side of the clip that secures the wiring to the speaker and pull it out.
4. Attach the clip to the new speaker
5. Mount the speaker using the supplied screws.
6. Push the grille back on.
This video (not mine) does a pretty good job at illustrating the difference. Compare the first 30secs to the part starting at about 1:05