I just bought the Neo IOn SP and hooked it up. Installation was extremely easy. There is an open port on the back of the HU used for the SAT connection I believe. Anyway, its just plug and play. In order to use the iPod you have the tap the CD button twice instead of the SAT button.
Neo iOn SP iPod solution for Mazda 3s
Pros: This is one of the easiest solutions, it is essentially just plug and play. It allows you to use your steering wheel controls to switch songs.
Drawbacks: OK, OK its definetly one of the more expensive solutions. But it does enable you to use your steering wheel controls.
There were only a couple of features I wish this unit had. First and formost, you cannot control the ipod from the ipod while its in the crade. Your only option is to use your HU and/or steering wheel controls. They recommend it you make a playlist so you are not fumbling around searching for a song while driving.
Another downside to this hookup is that it shows a totally seperate menu when playing music on your iPod. I have a 30 GB iPod that I store album covers on and I do not have the ability to see them while in the cradle because it shows a custom menu. This means that you have to take the iPod out of the cradle to switch albums or artists.
Overall I think this is one of the better iPod solutions to hook up to your Mazda 3. When I first came on this message board there were people who did not think it was possible without something homemade to mod into an AUX port. I would definetly recommend this hookup.