Your friends GTI (stg II) might be able to take you if you are both rolling. From a stop, he shouldn't beat you. Too hard for the GTI to keep the power on the ground, regardless of tire choice. Either of you running a manual? If you can afford it and are wondering if it's worth it, the answer is yes. Throw in an IC for good measure too, it helps, especially in the summer. Stage I for me was fun, but I quickly bumped to Stg II (APR) and noticed a difference in both responsiveness and power. It's a daily for me. Good luck deciding