About the ball diff and spool.
I took a look at some pictures of the Yokomo BD diff (BD-500A) and they don't look like they fit. But some people have said they do... Does anyone actually have one installed in a S400 ? What did you modify and can you use the same pullies with it ?
Theres also the problem of a replacement for the spool. I don't have any candidates for that one.
In the meanwhile, i was exploring another alternative. We could just machine the missing parts with CNC. I have a 3D model of a S400 spool in a eMachineShop .ems file but found out that it only becomes cost effective when ordering 20+ parts. If i find a cheaper alternative i could make files for the diff outdrives and all the bulkheads.