I wish I was close enough to take a look at it for you, really do.
Finding someone to work on it won't be all that easy - most mechanics are not radio guys (and I am no mechanic), all they will do is trade out the radio and antenna (after some basic checks).

Not being critical, like I say, they aren't radio guys.

ME? I'v made a living working on radio equipment for 29 years. Just can't effectively troubleshoot without being there to fiddle with it.

About tint: Some tints have a metallic ingredient, and this will mask radio reception on both AM and FM bands, altho it has been demonstrated that the effect is worse on AM. It sounds like the OEM tint does not have a metallic content, from reading the posts here.