Yes, K&N intakes can definitely increase power and torque. It's a guaranteed result. Installing a cold air intake is one of the quickest ways to add more airflow, power, and throttle response to your vehicle. Cold air is denser than hot air because it contains additional oxygen molecules that allow the cylinders to facilitate combustion more efficiently.
A factory air intake typically feeds hot air to the cylinders, while K&N high-performance air intake systems are designed to provide a smooth, unobstructed path for the air stream, keeping the air stream fresher and denser in oxygen. With a K&N high-performance air intake system, you get a guaranteed increase in power and torque. You'll get improved throttle response, slightly better mpg, and maybe a few horsepower, if you use a drop down panel filter. You'll get a little more from a cone filter with a thermal protection tube &.
A cold air intake, if available, will make the most of. Of course, as you climb the ladder of admission types, the price increases accordingly. More air equals more power, and oversized K&N high-flow filters will allow for greater airflow. While replacing only the OEM air filter with a K&N high flow filter will add power and increase acceleration, the biggest gains will come from installing a complete cold air intake system. Have more than 100,000 in one of the Audi filters and have used the appropriate K&N refill system to clean and grease the filter. Because cold air contains more oxygen molecules than warm air, injecting a larger volume of oxygen-rich air into the cylinders allows the engine to burn fuel more efficiently during combustion, increasing horsepower.
All K&N high-performance air intake systems are designed to increase airflow through an aerodynamic path that reduces turbulence, and filter designs that provide an increase in the volume of air reaching the engine. The trademarked red filter (usually conical in shape) on display or its kit may include a closed air box. As a result, K&N filters can retain significantly more dirt and particles per square inch of material than an average paper filter. An air filter helps seat the air more evenly instead of the air hitting the AF sensor in large chunks, which obviously makes the fuel more uniform. Using a K&N Power Clean is a better option, as an alternative, buying the refill and service kit that includes cleaner and more specialized K&N air filter oil.
For me, K&N filters don't actually filter particles enough for me to take a chance, so I simply put on a new OE filter every 12 months or so. Fitting a K&N high flow air filter is the easiest, most cost-effective and least technical way to increase engine performance. K&N high-performance air intake systems are designed to create a more aerodynamic path for airflow to the engine by removing the original intake pipe, which can create excessive turbulence, and also by using highly efficient airflow filter media. Most disposable, dry paper air filters work based on size. Dirt particles that are larger than the openings in the filter media are trapped, while particles that are smaller than the openings pass through them. And the third common problem, hot air pollution: hot engine air is ingested through the air filter.
Personally, I use K&N filters because I live in a dusty area and I usually spend more on paper filters than on oil filters. The amount of released horsepower you'll get from an air cleaner drop is negligible; Seeker80 is right that you can get MPG, throttle response and, by association, release (don't add, just open what's there) some power through the airflow but it won't be anything important. That said, I really saved money over the life of my truck by not having to buy air filter after air filter.