I took my RX7 there a few years back and had a horrible experience. My car was flooding(common problem with RX7’s), and they charged me an arm and a leg to search for the problem, and ultimately weren’t able to fix it. I especially didn’t like that they kept my car for so long, charged me for taking spark plugs off and putting them on, but were not able to tell me anything about the source of the problem. I can change spark plugs myself(and did). I pay a mechanic for their knowledge, expertise, tools, skills, etc. It’s understandable that they might get stumped every once in awhile. Charging the customer for it isn’t.