Every car in the COBB lineup is designed for the enthusiast from the factory.  With that in mind, it’s no surprise there are tons of different aftermarket options for every COBB supported vehicle.  The Focus ST and the Fiesta ST are some of the best selling “hot hatches” out there so it’s no surprise these platforms get a lot of aftermarket love.  There are so many parts available!  So many options make it common to see certain power adders installed that lack necessary supporting modifications.  Ahead will be the sequence of modifications that give your Focus or Fiesta ST increased power, improve drive-ability, and combine the appropriate supporting modifications to protect against failures.

Focus ST	Fiesta ST
The COBB Stage 1 Power Package for the Focus ST and Fiesta ST includes the COBB Rear Motor Mount, a High Flow Filter, and the Accessport.
Rear Motor Mount
First up is to replace the Rear Motor Mount (RMM).  This isn’t the most obvious best first modification since it doesn’t do anything to improve power but it definitely transforms the feel of the car.  The mount provides better traction, most notably during aggressive launching, where wheel hop is significantly reduced.  Also, since this is the only motor mount on the vehicle arranged perpendicular to the motor’s torque, it being more stiff helps the longevity of the other mounts.
High Flow Filter
COBB High Flow Filters are created with a proprietary woven cotton and metal mesh with a precision molded rubber base.  This design permits very high flow rates, minimizes restrictions, maximizes filtration and provides a long life filter.
Accessport
Now that you’ve got your ST, it’s time to make more power!  The Accessport is the best bang for your buck modification.  For $500, the easy to use Accessport can flash the Stage 1 map to your ST.  This will offer power gains that amount to the difference between night and day on a stock vehicle.  Aside from the power gains, the Accessport will also give you the ability to datalog/monitor several parameters the ECU sees in real time, change to other Off The Shelf (OTS) maps as you continue to add modifications (Focus ST – Fiesta ST), read and clear codes, and other cool features like launch control and flat foot shifting.
The Stage 2 Power Package replaces the factory intake with the COBB Intake System and upgrades the factory front mount intercooler.
Intake
Next up is the Intake. This modification will allow you to pick up some power, improve the looks under the hood, and make all the turbo noises much more audible!  The piece is easily installed and instantly improves the driving experience.
Front Mount Intercooler
Replacing the factory intercooler with a front mount intercooler (FMIC) is next up.  The factory intercooler can easily be over worked and overheated due to its small size.  Intake air temperatures increase dramatically on a warm day in a single pull on the stock intercooler.  That warmer air causes a loss in power.  With that in mind,  it’s no wonder this makes for a good upgrade.   With the COBB Tuning Front Mount Intercooler you can ensure that your engine is receiving the coolest possible air allowing more power to be made.   To take advantage of the lower intake air temperatures provided by the FMIC the Stage 2 Off The Shelf maps is only a few button presses away on the Accessport.
After you’ve removed the restriction from intake air and the charged air is nice and cool it’s time to open of the exhaust.  The Stage 3 Power Package does just that with the COBB Turboback Exhaust System.
Turboback Exhaust
Now that we’ve upgraded the intake side of things and cooled the charged air, it’s time to open up the exhaust. Not only will a turboback exhaust look good and sound even better, it will allow more free flowing air yielding greater power. The turboback exhaust consists of the entire exhaust from the turbo to the rear of the vehicle. The downpipe section is the exhaust piece bolted to the turbo. The remaining parts of the exhaust are included in the cat-back section. The Stage 3 COBB OTS map requires the previously listed modifications as well as the full turboback but the factory cat-back system actually flows pretty well. Peak power can be had with the COBB cat-back also installed but the map can be used with only the downpipe portion of the exhaust upgraded. However, if the most possible power and improving the sound and aesthetics are important to you, the cat-back is a good modification to include.
The recommendations after this level will vary depending on your goals. Some goals can be reached through different fuels and custom tuning while others will need bigger turbos and additional modifications. If you’re considering going beyond this list contact a Protuner near you and they can help achieve your goals!