The Gem State team thoroughly went through my 2003 Chevy Duramax bringing my truck back to a performance level where I can have confidence in its performance when I'm in the back country or driving the ALCAN. Joe and team were great at communicating with me as we considered the preventative items or if deferring made sense. If you have a diesel that that you want to keep for awhile, I highly recommend the Gem State team.