I just bought a new Motorcraft battery at my local Ford dealer. 84 month warranty and IIRC it was ~$70. It wasn't the same battery that came with the car - it has been obsoleted and the new battery has more CCAs, so I was OK with that. Hey, the stock battery lasted 5 years and only kicked b/c I let it get discharged by leaving a door open when I was working on my suspension.