i think their made of cheese to be honest. The engine/tranny does move around a fair bit.
If you've been down a 1/4 mile or just try and shift quickly at full throttle its quite difficult as a result.
Im going to a BSH or Neuspeed Torque Arm Insert, and ECS Dogbone mount. These are alot stiffer and you really notice it when shifting apparently, and their pretty cheap.