Here's the R2 from the "Encounter" kit. First, the box photos of the painted, unmodified version.

1. The top dome sections are off-center
2. The rest of the dome lacks detail
3. The three "snouts" are missing
4. The front arms have too much space between them
5. The head is too high from the shoulders
6. The insides of the legs are hollow
7. The center foot is too big
8. Some of the panels aren't correctly sized compared to their counterparts on other areas

Aside from that, it's not bad. :-)p

The first bit of surgery involved bringing the dome closer to the body. The front details were also off location, but some creative cutting solved both problems at once.

Cut from the top of one front vertical door all the way around the dome to the other one. Come down the inside edge of the door, then across between the two "arms" and back up. File down the new edges of both parts until you have a tight fit. White sheet plastic bits are the beginnings of the necessary detailing.