Cat 3126?? KWT300 , Where would I get better service at. Cols. Oh

I have a 2003 KW with a cat 3126. It is way short on power. I think I am going to take it to Cat. or KW. Which would be the best and cheapest?. Cols. Ohio area. I don't know if a independent truck shop could scan it properly with the Cat tools and don't know of a good one near by any way. Any one in my area that is qualified and knowledgeable to check them out, please let me know.

Cat 3126?? KWT300 , Where would I get better service at. Cols. Oh