Separate names with a comma.
... getting back on topic:
Amplifying the audio file, it is possible to hear people talking in the background, as well as machinery being used....
I have now proudly extracted the following messages from said letters:
YODA VS DAMN CF SPOILER
SLIM PAVED ROADS OF NYC
A CANDY FOR MODEL S VIPS...
You missed a dot, it should be:
That still doesn't work,...
Well, I usually just lurk, but since I can't resist a puzzle... here is piece 5.