Debate on, however:
One of the mics in my Core Sound HEB's died a few years ago. I sent it back to Len who quoted me some price around $500 +/- $100 (can't remember for sure). I requested them back, and they sat on a shelf until now. I sent them to DPA in Colorado, who said that for $320 they would replace the broken one with a brand new one matched to within 1dB. According to the tech I spoke with there, he said they'd do it, but that matching wasn't too important, as the variation is at max 2dB in units off the shelf. I know figures have been quoted here up to 9dB, but I thought this would be an interesting piece of knowledge for guys wanting to pick up ebay unmatched sets.
Also, FWIW, he said that he's seen a lot of Core Sound modified sets come through with one dead channel. He hypothesized that either they're all abused, or that there's something screwy with the power supply on these things.
I'm not a tech, I'm not an electronics expert, I'm just posting what the tech there told me as I'm sure this info might help some people's decisions down the line.
Cheers.