GM rolled out its redesigned HDs earlier this year, so we thought it would be cool to get a hold of one and then do some simple Fantastic Four upgrades to the intake, exhaust, suspension, and wheels and tires. The new HDs certainly look fresh, but they share more with their last-gen versions than you think. The suspension in the '07 HD is essentially the same as the '06 models, which means the aftermarket manufacturers only have to update the labeling on their lifting and lowering kits. We went with a 6-inch suspension lift kit from Bulletproof Suspension that was already in existence for the '06 models. The Duramax 6.6L diesel in the '07 HD is certainly new, if nothing else than for its aggressive, EPA-mandated emissions controls. Rolling Big Power (RBP) provided an aftermarket exhaust system to replace the OE system. At the other end, we nabbed a Volant intake system. Toyo was chosen for a set of 35-inch tires and the new 20x10-inch wheels came from RBP. The gents at 714 Motorsports in Westminster, California, installed the products onto the truck for us. Shall we begin?
Here is the Volant kit laid out before we started installing it. | 
A before shot of the 6.6L engine compartment in its stock glory. |
The Volant airbox slid into the empty space that used to be occupied by its OE equivalent. | 
The silicone sleeve was slipped over the factory tubing that leads to the throttle body. Then, the aftermarket intake tube was secured to the sleeve. These new diesels don't have much room under the hood, so the assembly at this point had to be pried a bit away from the rear of the compartment to fit the hose clamps over the sleeve. |
At the other end of the intake, the conical filter was dropped into the airbox and secured to the intake tube with a hose clamp. | 
After that, the logoed lid was screwed tightly to the airbox, and then the mass airflow sensor was attached to the new intake tube and plugged into the vehicle's data bus. There you have it, Volant's air-intake system gleaming from the dark confines of the HD's busy engine compartment. |
Here are the RBP and factory exhaust systems. RBP's 4-inch exhaust was designed to fit on the new emissions-friendly Duramax diesels. |  |
After removing the factory exhaust, the RBP turbo downpipe was installed right after the turbo. Then came the front extension pipe. | |