those dinky little crappy connectors would last. Something tells me those poorly designed clips would break somewhere between 2-4 years, assuming the car was driven every few days or so. The plastic portion that bends and gives is so thin to begin with, I'd be amazed if you didn't break one in that time frame...meaning you'd have to replace the harness again?
Yeah, I'm being stubborn on this and will most likely realize that everyone is completely right and I should replace the harness when I swap my engine...but we'll see.