Tying the ACK to the GPS involves running another set of wires from panel to your ELT location, and some soldering to make up a plug that they give parts for along with instructions.

I didn't do it for the reasons mentioned in my earlier post. Also, the ELT was the last item in my build and I was in some kind of a frenzy to get flying. I could still do it without too much trouble, but see no pressing reason. As I recall, the improvement in accuracy is something like 300' reduces to 30'. By far the most important thing is to get a 406 MHz ELT in your airplane, then obsess over the small stuff if you want to.