Everyone wants instant results when it comes to performance, and the most economical way to achieve it is by increasing the airflow coming into the engine. If that's all you ever do, you'll be a happy camper. Obviously, you'll want to do the same with the air exiting the engine too, but if money is tight, start with the intake system.

Aftermarket air intake systems have been around for a long while, and their benefits have been proven. To give you an idea of how really simple it is to bump up your performance and perhaps add a few more miles per gallon using an aftermarket intake, we followed along as Dependable Off-Road installed a True Flow XDi Extreme Duty intake on a late-model Dodge diesel.

Dependable Off-Road owner Steve Elliott went over all the possibilities, and in the end the True Flow system won out over an array of others. "On this application we removed the restrictive resonators on the stock engine and replaced them with smooth mandrel-bent tubing," says Elliott. "We replaced the stock air box with a high-flow canister. We changed the direction of the air filter so that the air flows from the inside out." Elliott calls it inverted airflow technology. According to him, this can increase the airflow more than 50 percent, which results in more horsepower and torque.

Here's a brief look at our installation. Keep in mind that certain new vehicle warranties might restrict any type of aftermarket performance upgrade, so if you're concerned, check with your dealership before you begin.