It's indeed a bit difficult to find the X45 drivers and software on the Saitek website. The trick is as follows: On the Saitek drivers page don't touch the left drop-down menu and select "Joysticks" in the right drop-down menu. Then another drop-down menu will appear where you can select the X45. After that, one more drop-down menu shows up where you can select your operating system version. Finally, there will be two links: One to to the Saitek X45 driver and one to the programming software.
Here are the direct links:
Saitek X45 driver and programming software for Windows 7, 32 bit
Saitek X45 driver and programming software for Windows 7, 64 bit
I am using the Saitek X45 under Windows 7 64 bit with DCS A-10C Warthog and it works flawlessly.
Concerning the TrackIR, I can confirm all positive feedback in this forum. I bought it together with a Track Clip Pro and it is really awesome.