Has anyone had any experience with Dyno Tune USA located in Watterton South Dakota. I talked with Andy at the shop and he said he has tuned many vortec 454's and had very good results as far as increasing hp and torque with a 1-2mpg increase as well. I was just wondering if anyone has had any experience with this particular shop or any other custom tuner. I did like the idea that he uses his dyno to make sure he has the tune right for your specific engine.