This is an interesting topic.
I watch in interest with people chasing B6 turbo rods and fitting them to BP engines (as Dann stated they are dimensionally identical).
Here is a good comparison of some different castings.http://www.clubprotege.com/forum/showth ... 6T-ConRods
I had a heated discussion with a person about the rods because I couldn't see what all the fuss was about. In the Ford/Mazda spare parts listing, the B6T, BP and BPT connecting rods are ALL listed as the SAME part number, and I didn't have a set to compare at the time.
I found out though that the B6T rod is definately beefier (I have now seen them first hand), BUT it is also beefy in alot of the wrong areas adding unnecessary weight. There are also different rod bolts used, and different machining/cast marks. Bottom line, they are probably marginally stronger.
In regard to the part numbers, it is possible that the part number listed them all the same due to supersessions in the spare parts system (in other words they all now use the same rods if you need to repalce them OE)
In my opinion, there is not enough difference in them to bother sourcing the B6T rods (unless you had a spare set, in which case you may use them). With the availability of good aftermarket rods its hardly worth thrying to source set, you would just buy some Spools or Eagles etc and be done with it and know they won't break.