Ok, 07 STi engine into 00 RS, and I've searched A LOT.
Here is my out of date thread:
Anyway, the starter just clicks, fast, machine gun style.
I've searched my butt off, and tried cleaning the terminals on the starter, the battery, I've checked grounds. I've also tried jumping it, so it's not a dead battery. I even swapped the starter out for a different one, and same problem. SO: I checked that the motor turned over, which it did, smoothly, so the rotating assembly is not binding. I've running out of ideas...