Hey Darryl, I'll be watching this one because I just ordered the Impact unit and I have these special IR emitters that Kevin recommended so I'll be able to give you some comparison data.

As for your original topic, are you talking about strictly stock? What the manufacturer claims or guys actual test experience? (I want to know both ) I've heard you can file down the emitter LED to reduce the distance from the element to the end of the tube (holding the required 9mm). Does that change range? Anything you need to do after filing, like polishing for clarity? What about shape? Does that effect range?

Good timing on this one, I'm sure I'll get all sorts of useful info.