I have a MacBook Pro that crashes Motion 3.0.2 when I'm trying to do something as simple as changing a fill color in an object. I purchased this laptop with specs that were supposed to handle Motion. (10.5.6, 2.5 Intel Core 2 Duo, 4 GB 667 DDR2 SDRAM, GeForce 8600 512 MB NVIDIA card).
I reinstalled the complete FCP suite and it still crashes. FCP suite works fine on my MacPro.