For Gearboxes:
7R Gearboxes have a thicker final output gear, different size shafts internally, and are much stronger nylon then the old #7 gearboxes. A gearbox with an orange output is definitely a #7R. Some of the newest 7R's are coming with white output shafts.
Parts and motors from 7R's are NOT COMPATIBLE with older gearboxes. Experience tells us that if you have one stripped older gearbox, the other is not far behind. Be smart, replace both.