How to properly set up the Google Analytics plugin?

This should be obvious, but I'm not finding an easy answer in the documentation.

On the page for the Google Analytics plugin, I see this line:

NB: To track all your subdomains separately you'll need to configure analytics and add in an extra line of code to the tracking code as described here (very easy to do): http://www.google.com/support/googleanalytics/bin/answer.py?hl=en&answer=55524

Question 1: I assume I need to add this line of code to the /mu-plugins/google-analytics.php file, right?

pageTracker._setDomainName(".example.com");

Question 2: Does it go before line 132 (site tracking code) or line 139 (blog tracking code)?

Question 3: I went to Site Admin > Options and put in my UA code. I understand that for each blog, users will need to get their own UA code and paste it under Settings > Google Analytics. However, for my main blog, do I need to go into Settings > Google Analytics and paste the same UA code as I did for the entire site?

Question 4: is there a recommended plugin that works with this to display Google Analytics stats in the users' dashboard?