Might be too far, but Bill Legall @ Millersound is a top choice for speaker repair/rebuild. Cheers,
If you live in NYC, OHm Acoustics is in Brooklyn and still supports and sells upgraded parts for most every speaker they have ever made. VEry convenient for a NY'er. Plus they are one of my long time favorites. I own 3 pairs (out of 6 pairs of speakers I actively run at present). One pair (OHM Ls) I bought in 1978 and recently upgraded myself using a combo of OHM and other parts.
No help for Mirage but thought I'd mention.
If you don't mind the short drive to Douglaston Queens check out Scott Gramlich from SG Custom Sounds. He did great repair work to my KEF 104/2s years ago and I've been happy ever since.
Here is the info I have.
4033 235th St
Douglaston, NY 11363
Phone number (718) 224-5083