Welded, it should hold at least as much as the R200.
Ok, the R160 and R180 flanges are fully interchangeable. Still don't know about R180 to R200.
Interesting fact, Subaru WRX R160 has a much larger input flange than our R180's. Why? Who knows.
I still need to order new bearings for my R160, since I couldn't get them off the R180 I got from Sterling, at least not in one piece.
Diff mount stud spacing is the same on the R160 and R180 as well, so no need for a new mount. R200 is a different story though, it's studs are a little wider (by 2mm, I think, I didn't really note the difference).