First of all for the un-infector (team changer), any gun (force class) and aimbot for Steam MW3 are part of a paid hack, though force class is avaliable for Tekno MW3 on MPGH in the private hacks section.
Team Changer/Uninfector: http://www.mpgh.net/forum/showthread.php?t=951992
Force Class: http://www.mpgh.net/forum/showthread.php?t=944548
To get the suppressed Desert Eagle:
1. Make sure you have the Desert Eagle Unlocked and it is weapon level 10 (might only need level 2 but I cbf to test)
2. Navigate to the address depending on the class you want: Class 1: 01DC085E Class 2: 01DC08C0 Class 3: 01DC0922 Class 4: 01DC0984 Class 5: 01DC09E6
3. Enter the value Hex 12 or Decimal 18 for suppressor or if you want extended mags Hex 9 or Decimal 9
This also works for the 44 magnum and MP412 though if you place a suppressor on them everybody in the game will have a suppressor floating behind them that will make a noise when you fire.