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.