Well that's true with any gasoline/diesel engine. It takes RPM to build HP. The key here is the torque curve. The VQ35 has a very flat and broad torque curve, regardless if it's at 2000rpms or 5500rpms. This is what makes the engine flexible and not so dependant on gearing and rpm to accelerate. Adding an aftermarket intake could impact the lower rpm portion of the torque curve making the car feel a bit flat and lackadaisical. As the incoming air speeds and becomes less turbulent in the aftermarket intake tract and across the MAF, the torque is restored giving the motor a quick surge in power. With the VQs, this usually happens between 3500-4500rpms. You can actually see the changes in the timing and MAF sensor resistance with a data logger.

 

blown Viper @ 7psi - 600rwhp at 2000RPM