There are many tube amps out there that will do just fine against your Panasonic. In fact, if you got sold on that one because it is "all digital" I'm afraid you've been had. It sounds like you have not had the opportunity to experiment with many different amplifiers. The Krell I spoke of was not a reciever, although they made one. It is an integrated amplifier.
The speakers you built are nice speakers. My initial hunch (now after reading all the other comments) is that you need to work on amplification, placement in room, and room treatments.
Regarding thin sounding, you can't blame that on all paper cones. I would disagree that this is why they sound thin. At least the woofer is used in many other high end audio speakers that are not thought of as "thin"
The speakers you built are nice speakers. My initial hunch (now after reading all the other comments) is that you need to work on amplification, placement in room, and room treatments.
Regarding thin sounding, you can't blame that on all paper cones. I would disagree that this is why they sound thin. At least the woofer is used in many other high end audio speakers that are not thought of as "thin"