First of all, this is a great product. It is of good quality, very easy to install, and does what it says it does. I recommend this to anyone who feels like they need or want more power in their car without having to do any hardware upgrades. I daily drive a mk6 gti in California, this mod makes driving so much easier and enjoyable. The hp gain and torque game is very noticeable. In addition, I also feel like I have smoother gear shifts (manual). I would have gotten stage 1+ but the highest octane in California is 91 so I couldn't. I honestly think that this car should have come stock with this extra boost. NOTE: you have to buy the uniconnect device with the software so that you can download the software into your ECU with your laptop and the OBDII port.