Okay - re P2Vs, yeah it does have a fan, Dirk proved that when he dissected his egg with photos a while back. And you can hear it too.
You said "I believe it has a fan but it overheats easily." What overheats easily? The transmitter causing burnout, or the camera causing shut down? Because I haven't really seen or heard much about this.
I haven't had any overheating problems with my P2V egg transmitter and I haven't really read about them either. Yes - the P2V+ is known to have problems, but I haven't really seen or heard problems with our egg. So I kinda assumed that was because it's already operating at a lower dB to start with, which means lower heat, and therefore, it's safer to boost. We wonder why the range is poor on the stock P2V - that's one of the reasons.
When you say " I think the base dB for the egg camera should be around 17dB", are you guessing that's what it is, or are you saying that's what you think it should be?
I've never had my FC200 shut down due to heat, but then again, I try not to fly if it's really hot - because I'm worried about the battery!