Cold air intake systems by themselves can add 8-10 horsepower to your car and are relatively inexpensive. A K&N FIPK V6 Intake kit would be a great option for any Mustang V6 owner due to its simple bolt-on installation and instant results.
If you’re not looking to spend $200-$300 on a complete intake system, a K&N Drop-In Replacement Filter is a less-expensive alternative that will still net you a good amount of horsepower. Plus, a v6 aftermarket intake or filter can be cleaned and reused, so you’ll never have to buy another filter, saving you money in the long run.
The newer 2011-2014 V6 Mustangs already put down impressive power number but by adding a 2011 Mustang V6 cold air intake you can get a couple of extra ponies to the ground. However, for a 05-09 Mustang, I would recommend an intake/tuner combo kit. In most cases, S197 Mustangs will not run if a new CAI is installed without an aftermarket tune. The car will start but stall out immediately.