Is the navi system really worth the $1,800 for a retrofit? Is it possible to get the complete kit cheaper or used? It looks to me that the system seems to have a lot of room to expand accessories attached to it. I have a 02' 4.4i. No need for instructions, maybe some direction on where I can find this beyond ebay, or craigslist. I prefer it to be used except the screen.

thanks again