I have the Iris Harrier (if that is the 'Sigma' one) - in fact, in my own little 'tribute' - as it was too cloudy here in S. Lincs to see the official flypast - on FSX, I spent a while flying around Norfolk.
Unfortunately, the lights in FSX set off the reflective textures in the HUD - a well known problem with using FS9 models (even in their "upgraded to FSX" form) - but annoying, nevertheless. Any help to get rid of that would be appreciated.
I also have the abacus Harrier, which is nothing special, but does look and fly rather nicely - it is the USMC paint, though.
I have just joined the Airix Modeller's Club purely for the benefit of receiving their 2010 member's model kit, which is two Harriers in special paint schemes.
If anyone wants one, they are available (currently to members only) at a good price and I would be willing to buy one for any forum member if you send me the cash via Paypal (or post). pm me. Or you could just join the club, of course...
http://www.airfix.com/official-airfix-club-membership/
Scroll down to see the kit and schemes.
Airfix are also planning release of a 1:24 scale (that's BIG

) Harrier GR.3 this year.
JD