It looks like this coil-over set-up utilizes the stock spring bucket. It's doubtful you can get a long enough coil-over in there to make this a good set-up. If you look at Carli's website you will see a coil-over set-up with the spring buckets removed and custom hoops fabricated in order to get a good size shock/spring arrangement. A lot of work. The spring in this system here will probably not hold up near as well as a big KORE VR coil (or similar full size coil) under the weight of the Cummins. Might seem like somewhat of a subjective analysis here, but it's very doubtful this set-up will perform as good as the conventional arrangements on the market. Someone buy it and give us some feedback.