why consider fixit OVER an r&d box?
everything is stronger on the r&d box.
Most fixit wrecks are due to 3rd gear separating creating a mess, r&d has a spacer plate and own mainshaft which is stronger than standard.

Has anyone here had problems with their r&d box?
what happened? and when?

keep in mind the ratios as mentioned in this thread, cause if its a direct top gearbox 6th gear will be like 4th on a standard gearbox.