[GuidoK]

IF it was the connector, that would be very very easy to diagnose.
I assume you've read out live data during the non starting issue?
If it's the MAF connector, you'd either see the L/S airflow or the IAT being way off.

Swapping out the engine to a completely different engine that was not featured on the platform because of running problems with the original engine sounds like a useless undertaking. The easiest thing to do on cars is keep the original packeage running.
Even swapping out the engine for another one of the same model and make is more difficult if it's a used one...you never know what you're gonna get.

Go to a competent mechanic. From what I've read in your particular situation, it's only been a parts cannon deal, not a diagnosing deal.