For those who don't kind a bit of.wrk you may be jnterested to know that the exceed light weight internals rorba 733 diff can be made to fit into a 411 diff. I forgot to weigh it before I began but with light weight internals and 1200 oil the diff weighs in at 22g. A new diff in the packet plus the extra shaft and 2 bevels (without oil) weighs in at 32g. It takes a bit of work to the out drives and mounting the main diff housing side main gear but when you get it together it feels better than the steel gears. I don't think the gears are a perfect fit so I think I need to do.some.more work on shimming but it does.go together.
Keep in mind that this gearset is not cheap for a few.plastic parts and alloy shafts.