The latest SP items are 3mm x 40mm but are pretty difficult to get hold of..
http://www.infernosonly.com/SearchRe...=16&Search.y=6
Plus you need to get hold of the new ball ends which are much longer, so when it comes to changing camber links its just a question of lengthening or shortening these.
http://www.infernosonly.com/SearchRe...=22&Search.y=7
With the 3mm x 50mm you have to physically change the ball ends which come in 4 different lengths..(dependent on where your running your links obviously..) the link below is for the harderplastic ones to go with the 50mm turnbuckles.
http://www.infernosonly.com/SearchRe...?Search=um112h
Have a look here.. (online manual for both RB5 & RB5SP) and you will see the difference..
http://www.infernosonly.com/Download...nuals_s/25.htm
Cheers
Nick