I posted a fix on my forum for the bluetooth issues that have been occuring with some MacPros. I figure the more people with this problem that read it, the better.
As many other MacPro users have discovered... it seems that the bluetooth reception range was less than a foot away from the computer... the mouse was skippy, and the keyboard would repeat characters often. It has recently been found that some of the Airport and Bluetooth antanae (and an unknown, unlabeled, unconnected wire) were mislabled (and in my case, only 1/2 were labeled) and thuse mis-attached after the bluetooth/airport option was added by Apple.
After much googling, I didn't find a decent tutorial or info on how to fix it, merely short posts on Apple's forums: "Swap 1 with 3 and yada yada. Your done." Also, to boot, only cable#3 and the BT cable were labeled (and possibly mislabled). So I figured it out after much research. I am also a visual learner and struggle with verbal or written instructions. I had to sketch it out. Here is the diagram I ended up making, and the steps needed to fix. If you own a MacPro and have horrible bluetooth reception, I suggest you look into this. Although look out, if something goes wrong, it may ruin your warranty.
So, in summary:
There are going to be four wires. For me, there were two unlabeled. One was short and disconnected (wouldn't reach the BT module), and the other was longer and attached to the upper airport port. Another was labeled 3 and attached to the lower airport port, and another was labeled (mislabeled) BT and attached to the BT module.
1. Detach upper airport wire (long, unlabeled)
2. Plug in previously detached short unlabeled wire into the upper airport port.
3. Unplug wire labeled BT from the bluetooth module. Put plastic shroud on it. This wire will be unused.
4. Take longer unlabeled wire that used to be plugged into upper airport plug, and plug it into the bluetooth module.
I have noticed that my bluetooth mighty mouse and apple keyboard work just as good as a wired keyboard and mouse, and my airport extreme reception has actually improved. All is good!