This track pack is bigger than the previous ones because it is self-contained and does NOT depends on a previous installation of the track in RH2003 or the 2002 season.
Note that if you have already installed the China track as (so graciously) posted by Steve, you will have to edit the GDB file from the 2002_Shanghai directory to remove the NAR20042 filter, otherwise you will have two China track in the season and anything could happen. The "right" (NAR2004) China track has an additional two little yellow lines on the right of its icon and should appear between the Brazil and Austria races.
If you have any problem, don't hesitate to contact me.