If you're looking to make your Duramax sound like a jet, there are a few things you can do. First, you'll want to install an aftermarket exhaust system. This will help your truck breathe better and produce a deeper, more aggressive sound. You may also want to consider installing a cold air intake kit. This will help improve airflow and also add some horsepower under the hood. Finally, if you really want that jet engine sound, you can install an electronic sound generator. This device will allow you to control the tone and volume of your exhaust, giving you the perfect jet engine imitation.