Vehicle Shudder problems of the 2009 Kia Motor Optima

The vehicle had three expensive problems in rapid succession. The first was the transmission which started a severely hard downshift on braking from about 25 mph. The whole car shuddered and felt as if we slammed on the brakes for a second. After troubleshooting, kia told us we needed a new transmission for $2700 with no help from kia. After this repair, not even two weeks later, the air bag light came on. Diagnosis from kia, defective sensor in the passenger seat, not covered by warranty and a $1500 replacement estimate. We decided not to fix this item because we were going to trade the car in on another make and cut our losses. The third problem which occurred one week later was a failure to start after parking the car for an hour at a doctor's office, stranding my wife in 95 degree heat. The car was towed to a non-kia repair shop as I no longer want anything to do with kia who will deny any claim against their so-called quality products and will be disposing of the car as soon as it is running again since kia does not stand behind its defective products. After three major failures in a short period of time we feel this is an unsafe vehicle.