revo diff cups and housings

[brushless losi]

1. has ne 1 tried rd logics diff cups, how r they and is there any modification needed like shimming?
2. the integy ones on this site r they ne good and do they need and modification as well?
3. will the rd logics diff cup fit the diff housing on this site and vice versa diff cups here fit rd logic diff dousing?
4. revo stock diffs last or get upgrades to have them on hand cause downtime sucks