I had the grills off and noticed a couple of small tears in the surround of a MW6511. I'm not sure how they got there, and I'm sure it makes any difference, as I wasn't able to tell just by listening to them, but I figure if it is a simple fix, then I might as well take care of it. Has anyone refoamed one of the older Polk drivers before? (Is it still called refoaming when the surrounds are rubber?) Can I just use any old 6.5" rubber surround, or do I need a proprietary part? Anyone have a good guide to the process?