Rated 5 out of 5 stars
Excellent work done.
Works fast. Even faster than the web interface :-)
Attachments are being successfully attached to archived Emails.
Too bad that there isn't a 'pro' version like in Outlook, that allows for 20$ per year to add contacts directly into Sugar.
The add on you're looking for is here: https://addons.mozilla.org/en-US/thunderbird/addon/opacus-sugarcrm-thunderbird/ :)