My guess is that even though I wish Matty's replacement would be a locally-produced morning show, iHeart will probably force-feed Elvis Duran onto WXKS-107.9.
The reasons I think this will occur:
1. The Elvis Duran show is produced and distributed by Kiss 108 owner iHeart through Premiere Networks.
2. Boston is one more of the few major markets where Elvis Duran isn't yet heard.
3. Now that Matty Siegel has retired (and yes, I think his retirement is voluntary), the major stumbling block keeping Duran from Kiss 108 has been removed.
4. With Elvis Duran's syndicated show in the morning, Kiss 108 may actually get less revenue but more profit. If WXKS's ratings go down (and rates for commercial spots correspondingly go down), remember that the huge salaries of Matty and most of the rest of the morning team (I suspect Billy Costa will stay with iHeart Boston in some other capacity) would be eliminated. The morning show probably accounted for a large amount of the station's budget. With a syndicated morning show, Kiss 108 might get less money but make a larger profit.
5. And with Boston, a major market, added to Elvis Duran's "network", the cost of national ad spots on his show would go up.
All in all, I would be extremely surprised if Elvis Duran's show doesn't take over the morning drive slot on Kiss-108.
The major idea of syndicated morning shows is to get stations to pick them up in lieu of producing their own local morning shows. By convincing a station to pick up a syndicated morning show, it eliminates a large part of the station's personnel budget and the station might make more profit.
I wouldn't be surprised if iHeart hasn't already begun the process to get Duran on Kiss-108.