Tyrone, J.Puma and myself are the 'pioneers' of the nav retrofit. I think all the research we put into it has helped a lot of people do the same. I never got around to completing my step by step write-up but Puma has done a good job of this. It is posted on this site in the articles section. If you have any questions, I would be glad to help.

First off, whether or not you have DSP sound shouldn't really matter. If you have this option then you will have to get it re-coded at the dealer after the retrofit. Another requirement is that your vehicle should have the 'High' on-board computer for the retrofit. While it is not mandatory, you will lose some of the nav features without it. To get around this, you hay have to replace your complete instrument cluster. Cost around $450 or so.

Secondly, the retrofit kits available in Europe (and from Roveractive on ebay) have the Euro radio module. This will most likely not work in North America due to the different radio frequencies, in particular the AM radio besides other issues. So you may still have to buy another new radio module locally which will cost around $450-$500.

Do your homework before you start buying parts...Good Luck!