To clarify on the IPOD kit, it comes with both an AUX input AND an ipod direct connect. I have the aux kit coming from a compartment at the top next to the windshield (so I can mount the EVO and plug it in; cord remains hidden when not in use) and the IPOD cord coming in the glovebox. This kit allows you to control both, and if you do connect an IPOD you can control it through the HU.
I recommended this rather than a new HU because many cars these days come with good HU installed, for instance, mine came with a 6 cd changer. Why would I remove that and install a PoS Sony? Depends on what you have already; a 2008 I would think you would want to keep the stock HU and add the connection, but if yours is pretty basic the cheaper more efficient option would be to replace the HU.
EDIT* - Also, the mount I posted is a hard neck mount, which wont wobble and shake when you drive. I just bought a goose neck which, while flexible, is basically a shaky piece of shit that I'm going to give to my mom because it bounces around too much. To each his own, just trying to help save some frustration.