I've been having issues with the Cobb intake (had it in for nearly 4 years). The lid from Cobb over the factory airbox bows up and no longer sits flush, allowing debris in the box. I've never really been happy with with how the intake fit from the factory anyways, with the cone end not being secure enough to the airbox lid causing it to sorta flop around, so I've had to secure it on my own.
Cobb has a new model of the Fiesta ST intake that seems improved, but I may look into other brands, still.
Cobb has a new model of the Fiesta ST intake that seems improved, but I may look into other brands, still.