I had a brief dialogue with JCat before doing my KS repair, (easy repair is a relative term, since never having done it, but i had zero problems and code never returned)
You MUST follow all the innovation behind remediating this problem for the life of the vehicle this includes: RTV dam around the upper knock sensor in a U shape. Removal of the sponge crap material (surprised nobody makes a replacement part that fits and is water proof) and then a horizontal dam made of silicone to prevent entry of water at the front of the intake manifold. (rear of manifold is of course left open so it can drain any moisture that does enter the valley)
That is how i did it, with Delco Knock Sensors from AC Direct on amazon, Delco Gaskets, and Doorman Knock Sensor hanress (0ld harness was still good, OEM was not available for purchase)
The total of the parts alone cost me $175 and that was thru online retailers, not "cheap" in my terms at least. however, the real savings is when you tear into it yourself.
One thing I can say is, DO NOT EXPECT TO BE FINISHING THIS IN 2 HOURS. Dedicate at least 4-5 Hours for this. For the cleaning of the valley detailed below.
Reason being is that your intake valley is probably VERY DIRTY and will need to be sucked out with a wet/dry vac. I did EXTENSIVE CLEANING to the entire intake valley area. And had I beaucou money I would have simply replaced the entire intake valley as well. I spent alot of time cleaning it. Trust me, those of you taking it to a shop to get this fixed, they will NOT BE SCRUBBING YOUR VALLEY CLEAN FOR A PROPER RELIABLE, LONG LASTING FIX.