got it today , just installed and tried it out 
happiness is a thing called tir 4
Good for you m8 
Whats the difference between the previous trackir system??
i was using tir 1 trooper theres a big difference between them
I havenāt had any of them (sniff) but I understand that the TIR-4 has a 46Ā° field-of-view on the monitor-mounted tracker, while the TIR-3 had 33Ā°. So you can move around more with the -4 and it will still follow you.
I donāt know about any other differences.
There is improved resolution as you go from TiR1 through TiR4, and improved discrimination between the target and other light sources in the room (noise)
It helps old people, in that it cancels the wobble from those old neck musclesā¦
Not that this has anything to do with me you understandā¦ 
The thing I love about it, is the ability to āleanā out of the cockpit and look along the nose of my aircraft (I canāt do this in IL2 though)
Iām going to be getting it shortly as the reports Iāve managaed to look at, suggest the improved field of view and much smoother trackingā¦ Anything to improve my immersion ehā¦
And yes, the lack of being able to lean out of my Spit, cockpit open, and taxi to dispersal is something I miss with IL2ā¦ great to do it in FSX though!