Was fun to do the project, and I'm fairly happy with the results - but I have the feeling a need an amp to really get the most out of the new speakers.
Welcome to the club. Once you have a system with amped speakers, you can never go back. Makes all the difference in the world.
When I started my stereo (after doing big systems and little systems in previous cars) I thought to myself, no problem, just replace the speakers and run them off the factory amps.
That lasted all of about 30 seconds.
You'll WANT an amp.