I just got GDP tunes through Ez-lynk and am very happy so far. We went back and forth a few times tweaking things to get dialed in. It had a ton of power to start but was a little smokey. I think this may have been due to the fact that I'm in Denver at altitude. I am very happy and the customer service has been great. Talking to others who have had GDP it was the customer service aspect that sold me on them. I really like the high idle with the SOFT switch as well.