Induction

A big part of performane in induction.  You can increase horsepower by forcing colder, dense air into the engine.  Below is listed a few ways you can do this.

Filters

The first step most people take in induction is replacing the factory air filter with a K&N air filter.  These filters offer increased performance over stock elements plus they never need replacing.  You simply clean them when they are dirty.  A new K&N air filter will cost you about forty dollars.

Another option from K&N is a filter charger kit which completely replaces the factory air box and bolts an 8" conical filter directly onto your mass air meter.  These kits generaly cost around $150-$170.

Ram Air

   Ram Air is a good way to add power by forcing colder air into the engine, but beware Ram Air also has the habit of forcing bugs, leaves, and other forein objects into the the car clogging screens and the filter preventing good air flow.
    One kit available is the March Ram Air kit which simply runs cold air from a scoop mounted under the front of the car to your factory air box.  This kit will cost about $140.
    Another option for Ram Air would be a functional Ram Air hood.  For about $700 you can get a functional Ram Air hood like shown below.  Kits include hood, K&N filter, air box, hoses, clamps, hood grilles, hood struts, and Ram Air decals.  These systems are said to add 20 horsepower.  For more info click on pic for link.

Cold Air Induction

   MAC makes a great Cold Air Induction kit for the v-6 mustang.  This kit places a massive K&N filter in the fenderwell to scavenge more cool air from under your vehicle.  I use this kit on my car and I like it alot.  It also comes fully polished with a chrome finish to enhance th elook under the hood.  A Mac Cold Air kit will cost you around $180 and can be installed easily with simple tools.  It took me just over an hour to do.

MAF Meters and Throttle Bodies

   Aftermarket Mass AIr Meters And Throttle Bodies increase airflow.  Any aftermarket 5.0 MAF should fit on the V-6, just make sure that it is calibrated for 19Lb injectors unless you have upgraded to better injectors.  As far as I know GT Throttle Bodies wont fit on the V-6 without serious modifications.  The stock Throttle Body can be bored out slightly.  There are a few aftermarket throttle bodies for sale at Need For Speed. These are made for the V-6 and should fit fine.  As for your Mass Air Meter.  The post inside can be removed for better air flow but may people are against it.  For more info and a how-to article go to Mustangworld.com.

Mass Air Meter

Throttle Body