The Tracking and Analytics has opened up for me. Yesterday I have done some Google Tag Manager's implementation to my site and it works nicely. One of the tag that I use is to track Internal Link Clicks. The thing is any button / text that are linked using Wix Code can't be recognized by GTM as a link click. Well I don't know why. Though linking using the traditional way works just fine.
Aside from that, I think there might be a gap of page changes in Google Analytics when using GTM as the medium. Actually the pageviews in GTM debug mode always triggers in every page changes, but the Real-Time report in GA just doesn't cycle with it. I don't think this is a problem with Wix, but well let me just say it here.