I dealt with Heister last time.
They were offering a lifetime drive train on their used cars at one time.
If you go to a big time reputable dealer, they aren't going to rip you off. It's not in their best interest to do so when they have 5-10 million tied up in inventory on the next lot. Plus they aren't going to put junk on the used car lot. I worked for a dealer once and I saw some NICE used cars get sent to the auction. They wouldn't put them on the used car lot for one reason or another. Might be bondo in a quarter panel, irregular tire wear, or could be anything suspect.
I've always preferred dealer purchases. Dealers know cars. You'll get a car that's just been fully serviced and most times new brakes. And I have something to fall back on as well as a little leverage to have some things fixed or replaced if you come to a sales agreement. Last one I bought I wanted a new battery and specified the brand. They did it.
I always carry my dad with me. On the test drive, I drive, he pulls everything out of the dash pocket. We never let the salesman come with us. You gather information there. Ask the salesman questions for the answers you already found to check where he's at on his information.
My dad's brother sold Chevrolets for 40 years in Raleigh. EVERYBODY in car sales knew him. That goes a long way.
It's the small privately owned used car lots to be careful of. Alot of them are low end auction cars. Look good from the road , and that's about it.