Personal experience: They go by what the computer shows the car is "supposed" to take, or by the speed rating on the sticker on the passenger door if you press it. They said I had to use the "H" (130MPH) speed rated tire unless the tire sticker indicates a lower speed rating is allowed. The door sticker shows a T (118MPH) speed rating for my car. Armed with this info they should allow a tire for the speed rating marked. (I don't know if the 93's were marked with the speed rating requirements.)
After two sets of COSTCO tires, two balance and rotates, and a warrantee replacement, I have nothing but positive things to say about their tire service.
They use hand torque wrenches only, and the manager double checks all torques. If your car requires 65 ft-lbs, make sure they note that on the order.
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Tom F