Hmmm....well, I tryed out FFUR v4, and wasn't too impressed. The units don't really look as good as the ones in Y2K3, and the many of the optics were the plain black ones that came with BIS, as opposed to the new ones in Y2K3. :-\
There were good parts to both mods, but I think Y2K3 has more, and its 300MBs less to download.
I'll stick to my good old Y2K3 mod
My 2 cents