Hi Skystar,
As a lovely looking little aircraft that E170 is, it unfortunately has nothing to do with Network. I have heard that it is over here for a few months on a contract of some sort, but I have know idea who.
All that new work over on TWY R is intended for the time been to be a shared apron (until at least it becomes an active TWY), so it is rumoured that more jets will be parked there. Hopefuly a few of them would be Networks (not 73's though)