Last year I purchased a Gen3 from Dobeck. System works great. Then I find out that they have a Gen4 that includes a gauge with adjustment buttons on it!!!!! I went to the Dobeck facility last Friday to have the new Gen4 installed on my 07 FLHRSE3. Matt, Chris and the crew were great at explaining the system to me during install. Once the install was complete, we set the gauge at what we felt was the correct AFR. Matt took the bike for a test run and adjusted a couple settings. The next day, and each day since I have ridden the bike and made some minor adjustments. Having the gauge to look at is great while riding down the road. I mounted mine so that I can also see the lights move from mode to mode. Between watching these two items and listening to the bike, it is easy to find where the bike runs at its best. The couple of questions I had have been explained in detail by Matt over the phone. Top notch product along with top notch service.