Looking at drive shafts from Mancini, 2 questions?

- Anyone know who makes these?
- What's the difference between the stock welds and the bored and lightened welds, doesn't seem to be much of a price difference?

https://www.manciniracing.com/driveshafts.html

I'd rather order from Dr Diff but he offers Strange with only a 1350 yoke option.
Would prefer to stay with the 7290

Thx