Google released the source code for Android 4.0 or Ice Cream Sandwich [ICS] to developers a few days ago, and there have already been a flurry of ICS builds ported to different devices since then ─ including the Nexus S, on which ICS was first seen, even before it was officially announced.
So here we go again, developer Brainmaster, who is quite well known and popular for his tweaked MIUI builds, has released a tweaked build of Kwiboo’s ICS ROM (Another ICS ROM which was developed for the Nexus S). The build has been optimized, tweaked, AD-Free with Dalvik tweaks, SD Card Speed Fix, EXT4 Filesystem Tweaks, Busybox installed … Usually one would get about 1200 Quadrants on ICS, but this build seems to be clocking a whopping 2419 quadrant score!!!
ICS builds have still not reached the point of being daily drivers, but you can always go ahead and get a feel of how ICS is gonna look on your device once the official ROMs are out, errrm.. or more stable builds , whichever comes first.
People who have tried this build on their Nexus S seem to have some good things to say about it. Read their comments and get the download links from this thread.
You can install it through CWM. Just be sure to wipe cache & dalvik cache before flashing. Enjoy!