eagle, it's still probably not as unique as mine (at least the attitude mine gives me, and being year-one on the VDC/H6)....
OP - the speakers are paper cone with foam surrounds. they've likely rotted out. Stock is 6.5" 8-ohm, but the amplifier can drive standard 4-ohm speakers just fine, and will put out roughly 40-60W RMS at that load (I haven't measured it, although I should do a proper reverse whack on the **** thing one of these days). Grab some Polk or if you've got the money, some Hertz Energy speakers in there. The factory McAmp is an amazing creation for what it is. You'll find the install goes surprisingly smooth, you can even re-use the existing speaker brackets.
Got the front doors done! | 1 Slick VDC
(jesus tap-dancing christ....have I really had this car for only 4 years but shoved 80k miles on it?!)
I wish I'd not have thrown my speakers out when they rotted out. Just don't cheap out on the speakers, there's way too much good stuff in front of them. This gear will keep up with almost anything short of pure SQ-oriented stuff.
Side note for stereo imaging in the cars:
don't fade to rear, destroys the imaging and introduces weird phase issues. replace the front speakers with something rather epic (I'll still recommend Hertz Energy), ditch the rear speakers or fade forward a bit. The subwoofer is a summed output of all four channels, so personally I'd say disconnect the rear speakers if you enjoy the front-only sound stage. I haven't had rear speakers hooked up in almost 2 and a half years now.
Outdated video (camera's mic was peaking, that was the distortion), system is capable of quite a bit nicer audio now, but same principle stands: epic audio quality at all volumes, even with just two front door speakers... I should also update my sig one of these days.