I wouldn't think the rotors and callipers are worth overly much, it's the hubs that are worth the money, right? (someones put s rotors and calipers on the hubs by the sound of it)
The cage would be worth a bit, but not sure how much?
FG front, well if it needs work, shouldn't be worth much, again not sure how much there (it better be a roundie front, hehehe).
Link to roller rockers at minisport, so you can come up with ya own price on second hand ones.
http://www.minisport.com/classic-mini-s ... ducts.html