How seamless is the Gmail/Google Apps integration?

It will require heavily coding to be able to break a crack in this process while violating the agreement of the software. I have a friend who does this for a living in my country by integrates different softwares but I highly doubt that this action is allowed in the States. If it is available it shouldn't be hard to find and try to figure out yourself.

ProsperWorks is built in and around Google Apps. It tightly integrates with Gmail, Calendar and Google Drive, minimizing the amount of data entry and providing the most up-to-date information at all times. ProsperWorks syncs with Google Contacts, sending you suggestions for new contacts and automatically updating the information of your existing contacts in real time. You can add a task or an event via ProsperWorks which automatically syncs with Google Calendar. Its bidirectional synching allows any changes made to be automatically updated between the calendar and prosperWorks. Finally, ProsperWorks Chrome extension allows you to manage everything including your contacts, leads, opportunities and tasks, right inside your inbox allowing you to work without ever having to leave Gmail.