Ozzzzy

I've searched through the forum on installing an Aux input into my Nak system by hacking the CD changer signals. There are several posts over the years dealing with this topic and my question is, is the 4 relay option the only way (low cost) to do this? After looking at all the posts, I'm a bit confused on which post to go by.

https://www.clublexus.com/forums/lex...em-stereo.html