Is the s16 by hrc ball-bearing? Now I heard about ceramic turbos being the best - but I don't see any aftermaket turbos described as such. Also, does the s16 have a split housing for the turbine?

it's all about the little things

Any ball-bearing turbos are ceramic ball bearing. Not much else can take the heat.

I don't believe there are any mitsu turbos built with ball bearing center housings. HRC offered the option once on 2GNT probably a year and a half ago, but i never heard anything else about it.