I need to run Android Studio 3.0 in root user to give permission to SDK manager (as SDK Manager is no longer Standalone) to install components to the root directory.
If you are getting Permission Denied errors for any component installation, this can be one of the solutions.
If you have installed Android Studio in the default Applications directory, this is where it will be. Else you can cd into it's path
cd /Applications/Android\ Studio.app/Contents/MacOS/
then run it as root user by executing
sudo ./studio