Trackballs for Curve 83xx, 88xx and Bold 9000 are the sames : but just the trackball, no the part around (round of plastic).
And, also, for the first problem, i meet it many times : you have to change the little part below the trackball - the dome who "clic". This part is directly on the mother board...
BlackBerry OEM trackball dome module - - Cellular Accessories | Mobile Accessories | Cell Phone