The ceramic balls ARE worth it... They do last a lot longer than the regular balls and some ppl think they're smoother too. I can't really tell the difference except that i do notice i don't have to put in new balls on each rebuild.
Brand wise, i just got the HPI ones... so someone should prob answer that one. They served me well.
The hara topdeck has the holes enlarged at the camber-link plate screws. So you screw down to the camber-link plate, not the topdeck.
The steering post screws are longer and use a bevel washer and o-rings instead of a plain button-head screw. That's it.
The camber-link plate holes are the same on the rear. Also enlarged so you screw down to the plate, not the topdeck. Hope that helps.