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The factory intake pipe is very restrictive and convoluted. It really flattens out and gets reduced in cross section as it passes over the top of the engine. 
It's easy to see the huge difference between the stock pipe and the Cobb intake pipe here. With larger piping through the entire intake tract, restriction has been greatly reduced. This reduces the amount of work the compressor must do at any given boost. Less compressor work means that the turbine does not need to extract as much power. This means less backpressure. Removing restriction makes power in a cascading way.
The stock Ford rear motor mount is super soft allowing a lot of engine moment. This causes severe wheel hop and increasing the power will only make this worse. The stock mount is made of low durometer rubber and has a lot of cut outs which are there to reduce vibration. The stock mount may reduce vibration but encourages wheel hop creating movement. We replaced the motor mount with Cobb's heavy duty part. The Cobb mount replaces the stock soft rubber with harder 85 durometer urethane in a billet CNC machined 6061 aluminum bracket. The Cobb mount has some holes to allow a degree of controlled flex to help with vibration but allows for much less engine movement. Wheel hop was eliminated with the Cobb mount. 
The Cobb mount bolts to the subframe and this bracket that bolts to the transmission case.
Eliminating wheel hop and engine and transmission axle movement reduces stress along the whole powertrain, even the charge pipes and exhaust system have less stress with less movement and pounding wheelhop. Even though the wheelhop was gone, we did not notice an increase in noise or vibration like we feared would happen. The Cobb mount should be mandatory even if you have a stock Focus ST!
Next, we removed the stock exhaust and downpipe.
