You have to remember that the longer the drive shaft the lower the critical speed (the rpm at which it will vibrate apart no matter the balance or strength) which is why on semi trucks , pickup trucks, and longer sedans they use two peice.
I drive a kw (semi) with a tuned up 600 hp cat pushing 2000 foot pounds of torque and I have never broken a drive shaft but I have knocked the teeth off the gears on 4 diffs
So by having two shorter drive shafts you can have a much much higher rpm with less vibrations. The only draw backs are more weight, the necessity to make sure alignment is perfect, and the weak carrier bearing bushing used on most factory setups. But if you went with solid motor and Tranny mounts and a very strong and stiff carrier bearing bushing then you would have less u joint deflection, could run a ideal u joint angle with shorter shafts for a higher critical speed. Should be just as strong if not stronger then a one piece setup but it is definitely more complex which means a little more work to get right. Even with out changing motor or Tranny mounts just getting a better bushing for the carrier should make a 2 piece just as good as a one piece and you should be able to go a faster speed with less vibration then a longer one piece will have.
