Make sure you let the workshop know you want a good job that's not rushed but you need it back by a certain day or time. If you give them an open time frame then other cars will be given priority over yours. Never offer to pay the mechanic before the job is finished.
Some probably still do, but it is a really truly stupid way to run a business. Mechanics that intentionally sabotage their customers simply won't last, and eventually go out of business. Depending on where in the world you are, far more often than not, mechanics won't sabotage your car.
No more removable “chip”. To match the ECU to the vehicle, it must be programmed with the proper calibration. Even if you just wanted to “try it out”, many vehicles would not start due to the antitheft system. ... Swapping without proper programming or updating will result in a no-start condition on these vehicles.
A trustworthy mechanic is always willing to explain the problem to you and show you the proof. If the mechanic is comfortable working while you watch, you can trust him. If the mechanic is apprehensive about letting you take a look, you'll never know if he is being honest. Go with your gut.
Most repair facilities can and will offer price matching. Always check RepairPal's estimator for a fair price range on your service. And if you're visiting a Certified shop, it's required. Always negotiate the rates and prices before the work is performed—you have less of an advantage once the service is completed.