Never having a diesel before, I came into DSI and asked questions about diesel trucks... Bob and Daryl were very helpful and answered my "novice" questions. Now that I have purchased a 2007 Dodge with a 5.9 Cummins engine they are still helping me learn about what needs to be done to properly service and improve the performance of the Cummins. On a trip to California I called them an asked question on "Bio-Diesel'... They were just as helpful over the phone as in person. They have performed the basic maintenance services and helped me choose the correct aftermarket equipment to give me the best economy and power. Thanks guys! I really appreciate you helping a "newbie" get started with diesel trucks! John Bedlion