Simple ways are the best - the new Update-TASTE.sh machinery.
The update process will simply enumerate inside the install/ folder, and execute the scripts there in sequence. This way each of the TASTE maintainers is responsible for his own stuff (e.g. making sure he/she cleans up the 'leftovers' of previous installs and installs only the new ones, etc). If any of the scripts exits with non-zero, Update-TASTE.sh stops.