Why not just buy TIR 5?? It's the price of two PC games and will let you use it in nearly every flightsim there is + games like ARMA II and certain driving games/sims too.
I have had TIR 3, 4 and now 5 and I must say I am overall very very pleased with it. Definately worth the money. Also, it's very accurate and responsive, and with the track-clip pro with the IR diodes it just sticks to your headset and you can get rid of that silly cap :p
The only downside I can possibly think of with the TIR is that it doesn't like bright light sources, other IR devices or direct sunlight. Myself, I sit with my PC against the West so that in the afternoon I can get some direct sunlight in here from my 9 o Clock position. Even though, the biggest problem is being blinded by the sunlight myself, the Track IR rarely looses track
I paid a total of just under 200$ total to get it shipped to Norway, and it arrived within a week