f,

They are usually available for sale on e-bay in the $150.USD range for 400 watt.

Also, look for the Dolby surround sound processor.

I replaced the SC-816 on my S70 with the SC-901, Dolby processor, center speaker and Dynaudio tweeters. The other speakers are OEM and of middling quality. Unfortunately, the Dynaudio speakers in the C70 won't fit the doors of the S/V 70 series.

But, since the imaging w/center speaker and processor is from the front, like a live performance, having 1st class dash speakers probably gives me 80% of the presence of the C70 system.

I've had no problems with either the 3 CD changer or the 6 CD changer.

Good luck,
Bryan