I was fiddling around with Subi diff's for my 1600, and found the below diagram on Ozdat a while ago, never tried it, might be worth a try if you know a top machinist and welder? I'm sorry I dont know the original author of the diagram, so I cant give credit where due.
As for the rallycar, it's a bit of a bad example, he's very hard on thing's and they get a pounding!! I know in the old car, a MY99, the drive shafts got rebuilt every 2 events, mind you the front diff and dog box went back to Mr.Frank at Modena for a full rebuild after every 4 events or 500km! told you he was hard on it. He changed to the fancy $1500 per driveshafts and they lasted a lot longer between rebuilds. I'm not joking when I say it cost's more than $50 a competitive km with these puppies!!
After all that, I'd try the Subi halfshafts, if it's a R180 then most likely it's STI which are stronger. Hope this helps a little. I have a R160 subi LSD for sale if anyone wants one for there pedal car or Subaru??
