I was wondering what it would take to add a navi unit to my car which has a regular Pioneer system. I was thinking of buying a navi unit from ebay and installing it into my car, which does not have a navi. Is this possible and has anyone ever done this before

 

The GS guys have done it. You will need to fabricate a few harness, but its not THAT hard. Take a look at this thread, you will find a link of bananGS's conversion.

https://www.clublexus.com/forums/sho...d.php?t=167452