Ask what their SHOP HOURLY RATES ARE!
This information could save you money. For example, one shop prices a water pump job at 2.5 HRS. In labor. Their SHOP HOURLY RATE is $45.00 per hour. That means charging you $112.50 in labor. Another shop charges$70.00 per SHOP HOURLY RATE. That comes to $175.00 in labor. Just by asking what their SHOP HOURLY RATES are you saved $62.50. Every shop sets their own rate.
You will also appear as a careful shopper. They will think twice about over charging you. Ask them what are your chances of having your car serviced by a certified technician. In the auto repair industry mechanics are always coming and going. Training new people are always happening.
After all this is your money and vehicle you are entrusting this shop to. So don't be afraid to ask!