The APR K04 Turbocharger System is a drop in turbo upgrade that dramatically increases power. With this upgrade and appropriate software, expect power similar to a heavily tuned Golf R, S3, TT-S, and other high end vehicles, as the K04 comes standard on those vehicles. Transient response is lightning fast with minimal lag. Power comes on quick, and stays strong through the entire powerband. Best of all, the system is designed as a budget upgrade compared to larger turbocharger systems, and only requires minimal hardware, most of which is available to APR Stage 2 customers. Turbocharger: APR uses Genuine Borg Warner components. The heart of the system is a Borg Warner K04-64. The CNC-machined billet compressor wheel and stainless steel exhaust manifold are a substantial leap in technology, performance, and reliability over the factory unit. Unlike the off the shelf K04-64 unit, APR's unit is customized. We integrated the DV into the compressor cover, just like the factory turbo it replaces. In doing so, clutter and complexity is removed. The DV mounts to the turbo, eliminating several potential boost leak points. We've also removed the turbo muffler, and added an ez-flow silicon hose. It's a simple and clean install. With many thousands of these units sold for more than a decade, we can confidently say these turbos are powerful, and reliable. Install hardware: We don't cut any corners with this system. All gaskets, nuts, bolts, washers, studs, and one time use clamps are included with this upgrade, making install as headache free as possible. Software: APR's Stage 3 K04 ECU Upgrade is not included with this purchase as this is a bare bones kit. Please visit your applicable vehicle ECU upgrade page for more information about the software, including recommended and required hardware, power figures, and other details.