Hi Michael,
Just took a peek at your website and the first thing that jumped out at me (almost literally) was the subscription box. Frankly, this is annoying, but I hear it works, so it's your call.
(Tangent: Possibly making it look more visually appealing, for instance a sticky note style pop up, and made it more unobtrusive, like up in the corner or just covering a bit of the content.)
Okay, I know you said not to discuss aesthetics, so I'll move on.
The next thing that jumped out at me is the date - last time I checked, it wasn't the year 106. That should be an easy fix for you.
I absolutely love that you don't have the recording automatically play. This is something that irks me with other sales letter sites.
Since the letter itself was quite long, I actually just scanned it (don't have too much time right now, but may come back to read it in depth) and wanted to let you know about the first couple things I noticed.
~ Teli