Probably no other company knows more about performance intake kits that K&N, makers of the world's best air filters. They offer their performance intake kit number 77-1548KP for Jeep Commanders with the 4.7 V8 engine (a kit is not yet available for the 3.7 V6 or the 5.7 Hemi V8). This performance intake kit claims a 7.96 Horsepower gain over the stock air filter setup. Each kit comes with detailed instructions to facilitate installation.
K&N also offers another intake kit, the 63-1548, which claims an even larger Horsepower gain (9.47 HP), however it is not street legal in all 50 states.
For owners of Commanders with the 5.7L Hemi V8, there is the K&N replacement air filter. While not as effective as an intake kit, these filters last a lifetime and allow more air than the stock OEM air filters.