Upgrade SATA connection on MBP 3,1
My best suggestion is that you try. Worst case it will downscale to SATA1/2 speed if it's all it can handle.

The easiest way to determine if your board will support the speed of SATA3 is to have a look at your Serial ATA settings in system information and check your link speed. It will show the supported speed and negotiated speed.

I have a MBP 6,2 which does support SATA3 on the board. I know my MB 3,1 only support SATA1, however it was always a low spec model compared to the MBP range and it may have been limited to save cost.