Steeda and WMS both offered tuners in their kits, and Cory feels that a tuner with a cold-air kit is needed. "We changed the spark tables, the fuel tables, and all the stuff you can change," Cory says. "The control of the variable cams is important. We changed the environmental things like high- and low-speed fan "on" time, the idle, shift points in an automatic transmission-equipped car, the rev limiter, and got rid of the speed limiter."
Wall agrees. "The tune we have is supplied to us by SCT, and it is an optimal tune developed on the dyno," he says. "It is not on the ragged edge, but a tuner will only find a few horsepower tweaking it. Most of the gains seen with a tuner come with changing the transmission shift points, rev limiters, and such."
"WMS sent us the kit, and we tested it on a car out here in Longwood," says SCT's Charlie Mahoney. Mahoney adds, "We checked the air/fuel ratio and the fuel trims, and made sure all of the numbers were set for a cold-air kit rather than just a tune itself. We didn't have any problems getting the tune into the computer. When the project was started, it was just like any other we had worked on before. Because the '05s and '06s are fly-by-wire, we had some issues concerning that, but we had no other problems other than the ones we had tuning computers in other models."
The other side of the coin is the AEM kit, which did not come with a tuner. "We developed the intake to work with the factory ECM and program out of the box," says AEM's Lawson Mollica. "The kit is a tuned inlet designed to work with the rest of the motor. All the kit does is move more air into the throttle body, though with a tuner, you can get the car to perform a bit better."
The AEM kit we tested was a prototype that included a spacer that bolted onto the intake manifold behind the throttle body. While our kit came with the spacer, Lawson says that less than 5 percent of the kits AEM produces come with the spacer. Designed to increase plenum velocity, there was no gain in power from using the spacer.
To really take advantage of the kits, even the ones that come with a tune, taking your Mustang to a proven tuning specialist may help in utilizing all of the power potential that one of these kits offers. Whether you get a kit with or without a tuner, the numbers and the track data don't lie. The colder the incoming air, the higher the horsepower.
The Steeda kit features gasket stripping that seals the filter box to the inlet tube and the airbox to the hood of the car when it is closed. Through the opening, you can see the MAF sensor protruding into the inlet tube. | 
Except for the fact that the Steeda kit uses the stock inlet tube, the overall design of the kit is similar to that of the AEM. To avoid making the same mistake we made by having the filter fall off with the AEM kit, we cleaned the slick film off the mouth of the filter before tightening the hose clamp that attaches it to the inlet tube. | 
Accompanying the Steeda kit was an SCT XCalibrator tuner with a supplied tune developed by Steeda. Hooking up the tuner is as simple as plugging it into the computer port under the left side of the dashboard. |
Flashing the tune into the computer is straightforward, as the XCalibrator has easy-to-follow instructions that come up on the screen. D'Amore loaded the program in a few minutes, and when it was done, we were ready to rip off a few more passes. | 
We were monitoring the A/F ratio to make sure the car didn't go lean with any of the kits. We also monitored the fuel gauge to make sure the car's weight didn't vary too much over the course of the day. | 
The differences in the stock radiator cover (bottom) and the WMS replacement (top) are quite apparent. The fresh air comes through the slots and the rectangular hole on the WMS kit. The WMS cover is also larger and bolted right up. |