I used a set of Motive 3.55 gears in my '86 GT about fifteen years ago. Not sure of the quality of their currently produced sets, but that one was fine. Just make sure whomever installs them knows what they're doing and does it correctly with the right tools.
Yeah I originally ordered the ford performance gear and kit. But the gear was out of stock and was going to take three weeks. So I went back on and they suggested the Motive gear and took 10% off (which was still more than the Ford performance gear), so I went with the motive. They said I could use the Ford Performance installation kit that I ordered but I went ahead and ordered the Motive installation kit with the bearings. I feel like Motive makes the kit be for their products.