It is the Stage 2 with the Roushcharger kit using the TVS2300 supercharger installed by Maximum Velocity Performance in San Antonio. The tune is a custom one by John Lund done on a Mustang Dyno. The Roush Tune that came with the kit produced 459 RWHP. The Lund Tune produced the 531 RWHP. This is actually much better results than I expected. These are some good folks at what they do!