Ok, here's the basics.
You have a knock sensor, just a simple microphone. It hears things, sends a signal to a filter, it filters out regular engine noise from bad engine noise, when it hears bad engine noise, it lets the ECM know (passes the signal along, just like a crossover). The filter is specific for each motor. The Syty's have the filter built into the chip. The Buicks have this filter in the ESC module, which is external. The Buick knock gauges pick up that signal after it is filtered. If you do it before, you'll have a light show of a knock sensor. To do it on ours, you have to pick the signal up after it is filtered, off the chip itself. I was under the assumption that one of the ECM pins had the filtered knock signal on it, but with my setup wired for that, it didn't work. So you can rig up a knock LED (this has been done on a couple trucks) off the memcal itself, or run a Buick ESC off the stock or a separate knock sensor, and then run Buick knock gauges. That's all that we know will work now. There are more options, but they'll take some work & testing. I don't have time to chase this project down.
Brian G