I'll say it again; the factory 5-pin harness will accept either ECU with no changes. The un-used side of the 4-post resister just dead ends.It was the power supply to the 5-pinner. The 4-pinner takes it's power from a different pin,no biggie.
You are free to change your wiring of course, but what happens when 500 miles from nowhere your 4-pin ECU dies?And all you can find is a 5-pin replacement....... just something to think about.
