As far as I know, no one has cracked the code on these LS engines yet to reprogram the ECU.
I do not believe there are any differences in drive train either. That would not make much sense from a manufacturing point. To have to retool just to make a different transmission for the same frame tractor with the same engine with different ecu programming.
From what I understand, there is a difference in turbo size from the 45hp to the 50 and above in the XR models. Though that might be a bit off. I know they are different and I have the smaller one. And it is very small!, but I can say I have a turbo!

Other than that, I belive it is just ecu programing that is the difference. Before too long, someone will 'crack the code' and we will all be driving around more powerful tractors :laughing:. But I wouldnt hold your breath. LS is not exactly John Deere with Right to Repair BS.