I don't know if there's a mailing list, I just bookmark the shell shocker site and check it every day (if I remember/am looking for something in particular to go on sale).
I'm likely not allowed to post a direct link, so go to newegg canada's site and look for the shell shocker icon.
The URL is a generic one that updates twice a day on weekdays and once on weekends with a limited time deal.
It should be obvious you have the proper URL to bookmark because it says ShellShocker right in it.
Anyways, it arrived today. Preliminary results are good - will have to wait for the old one to drop out/have breakups to see how it is for sensitivity.
Despite higher power levels for CHCH and WBBZ, can't get them.
It is showing on par or better for all channels so far, despite an extra (internal) split vs the old one.
When I don't have anything to record (likely this weekend), I'll strip down to just input cable, no amp, no split and see how it does.