Take the Milage as a very rough guide only, would you buy a 30,000km car with torn leather seats and low compression on motor and 5 leaks?
When Digital displays go bad people replace them so they will have different mileage anyway sometimes.
The condition of the car is best indicator.
Also don't go bargain hunting or turning away a car because of a high price before you have seen it in person most of the times the cheap cars are selling for cheap because they are not working out for the person who owns them buy something that is a reasonable price for reasonable condition I saw a z30 sell for $20,000 but it was Mint in every aspect
You really have to be your own judge and listen to your own gut feeling and opinions when buying cars because everybody is going to tell you different things.
Look at a few cars and make a check list that has 1-10 markings for each section e.g interior engine. Look at 5 Different Cars and fill that list out, and then compare your results with the prices and get what you reckon is worth it the most.