If i use Cartaro to manage my geospatial data handling website, will it be possible to use or integrate other Drupal distributions or modules to customize other sections of my site?
You can use Cartaro with most other modules and distributions. That is exactly one of the strengths of Cartaro compared to other webmapping solutions: you can extend the functionality of the system easily with the bunch of exising Drupal modules. However you have to make sure that the other modules you plan to use do support PostgreSQL. PostgreSQL with PostGIS is the required database backend for Cartaro.