I've seen some pretty wasted throttle shaft bores in my day (typically on manual trans vehicles) that didn't create a high idle problem. Not saying that yours isn't, but if it were mine, I think I'd look elsewhere before spending the dough on a reman one. Usually the worn shaft bores allow the blades to seat further into the venturi bores sending IAC counts off the scale trying to compensate for the lack of minimum air. It also brings down the TPS voltage to below the recommended .5V. I usually set mine at a minimum of .75V as it seems to help throttle response and drivability in general. So while worn shaft bores are not a good thing, usually they don't contribute to a high idle condition. Just some food for thought.