Well its not your coil packs..... so dont even waste your time with them and hopefully you can get your money back. If its sputtering like that commonly it is the front (primary) o2 sensor that has taken a crap or has a damaged wire. Swap an o2 sensor with a buddy if you can since they are expensive. Many people might even suggest that there is a tune issue but I wouldnt think so because it ran fine the day before with out you doing anything. If you dont have a CEL its hard to say what it could be for sure. If you were boosting and driving hard the day before it is also possible the Fuel pressure regulator on the passenger side fuel rail is stuck or not working. Check the vacuum line that goes from the FPR to the intake manifold, its only about 2in long and commonly cracks/splits. Maybe it was just sheer luck that it split and now you dont have proper vacuum to it under pressure because the pressure in the I.M under boost will make the crack/split widen causing the FPR to just stay closed.
as for that random connector..... not sure about that unless you could get a really clear pic of the harness leading out of it. Almost looks like the connector on the purge solenoid but I dont think it could reach to there.