Hi Dieter,
1. You can turn off the tracking token in System Settings ->E-mail, but If you do this, the auto track of replies won't really work very reliably.
2. You would normally only use the Outbound profile in the Email Router if users will be sending emails through the Web Interface without outlook being open. If you use the email router to send, emails will not appear in the user's sent items. If you use outlook, emails that are sent via the web interface will be downloaded and sent via Outlook. Emails sent via Outlook will be added to CRM if the user selects 'Track in CRM'. There is no way of forcing a user to track an email in CRM - but you you can select to track 'E-mail messages from Microsoft Dynamics CRM records that are e-mail enabled. ' in the user's options - which will auto track inbound emails.
3. The mobile email is harder - Dynamics CRM 2013 has more support, but in the meantime you would either have to use a forward mail box, or use a third party solution such as http://www.cwrmobility.com/ to get mobile 'track in crm' functionality.
hth