I was at JL Audio for a bit over 5 years doing tech support, the 6W-O's are designed to be in very small sealed enclosures, the most likely reason that the surrounds failed on those particular woofers was over excursion, the C5-650CW's are the component woofers from the widely acclaimed C5-650 systems, they are designed as infinite baffle drivers, they do not need an enclosure, their suspension is inherently more compliant to the mounting you have in those rear corners.

 

Thanks WCBEN. The new speakers provide a very good quality of sound.

Kudos to Crutchfield. I bought the C5-650CW's from Crutchfield. The speaker frame mounting holes needed to be made larger so I put them on my drill press. I know... mistake number one, never put speakers on a drill press... anyhow, I inadvertently caught up the butyl edge with a drill bit. Suffice it to say it was damaged and unable to be installed. I called Crutchfield and explained the situation, expecting maybe a mercy-related discount. To my surprise, they sent me out a free replacement even though I told them it was my fault. Result: Instant lifetime customer.