Want a specific car. My fear of getting ripoff makes all ads look like a scam. What to do?

I am looking to buy a specific car with a specific year. The car is not that rare, but not that very common either (see only 5-6 ads on Donedeal for the whole Ireland at the moment). All of them either the private seller gives a scam vibe when initiated, or my research of the dealerships that sell this car at the moment are all negatives. So, I think about what to do.

1. Ask my trusty local garage to source the car: I've never done this. I feel like, are they going to put up with my complicated wish because I really want a specific year, and also the budget, etc. I guess I could try but I sometime think are they really doing it, and how long will it takes.

2. Use the mechanic: I heard that people bring the car to the mechanic when viewing the car. I'd never done this, and since the car is mostly scatter all over Ireland, I feel like a hassle to find a mechanic that is good, in that area of the car, available at the time of viewing. Like for example I see the ads in Galway and I'm from Cork. I have no idea which mechanic to go to.

For information, the car is Lexus CT, not exotic choice or anything. I prefer the look of pre-facelift which is 2011-2014(1).