Back when I decided that I wanted to step up my cars performance I wondered the same thing and when word got out among my friends they all said "go with my guy, he's the best". What I did instead was take a couple of seasons and just watch.....watch who was going fast, who was spinning their motors hard and always race ready, meaning they were staying together all year. If there wasnt a sticker on a car of interest I would ask the guy who does his motor work and nothing else. At the end of a couple of seasons the vast majority of cars that fit my criteria were pretty evenly split between 2 shops, and one of them was closing the doors to go work for Reher and Morrison. I went to the other shop, talked with the owner for a bit and went from there. He showed me his shop, but I told him I wouldnt really know much about what you were showing me anyway and that his attitude, personality and reputation had already sold me. 13 years and thousands of rounds later I have zero regrets about my choice. In all those years I had only 2 failures of any kind, and they were parts failures, nothing within his control. All machine shops are gonna tell you "warm fuzzies" to hopefully win your business, but I look at what their product is doing at the track long before I talk with one. Just my .
Ken.