New tint job = messed up radio reception

[doobyscooby]

I recently had my 05 WRX tinted with Madico Onyx film, but now some FM and ALL AM reception is lost and/or interfered with. When I put my finger to the rear winshield, the reception comes back. I was ignorant of this possibility when I had the car tinted, unfortunately.

I know that Madico Onyx is a semi-metallic film and have read on some tint installation forums that the film needs to be grounded so one fix is to make a tiny slice from the rear window by the defroster line. Has anyone had experience with this and is there a fix that does not involve slicing the tint or makes the slice not noticeable? I had the windows tinted only 35% in the rear, so I think that removing a portion will be very noticeable as opposed to having the slice done with a limo tinted window and covering with vinyl.

Some may say that I should've gone with a dyed film, but I think that there has got to be a way to keep this tint job and get my radio reception back.

If there's any interest in how it looks, I'll post pics. It's a crystal grey metallic 05 WRX with 35% rear and 55% front.