Technology has come so far in such a short amount of time. I have a really good sound system that I put in my car. The base model Camaros (in 1994, at least) only came with 4 speakers...my car didn't come with the speakers behind the rear seat.
Anyway, with the exception of my head unit, my whole system is from Rockford Fosgate...and I haven't personally heard any components sound better. I have 4 3-way speakers, 1 10 inch sub, 900 Watt Sub amp, 1500 watt speaker amp, and a 1000 watt capacitor. I spent more than I, personally, should have...but I got an amazing deal overall.
My mom's Passat has a Monsoon system and I'm never been impressed. The other thing is that I don't know of any car company that's been able to give a sound system that could stand up against the aftermarket. Nonetheless, I would love to see GM squeeze at least a 10 speaker sound system into the Camaro, from JL...since I don't see Rockford Fosgate being an option. Those 10 speakers include a center channel and sub. I say a center channel because I've only seen them used in luxury sedans and I think that it adds an excellent dimension to the sound quality.
The other thing I wanted to add was that in seeing spy shots of the interior the only thing that made me a little sad is that we haven't seen a screen like the G8 GT (for instance).
I don't really want GPS/navigation, but I do want a nice 7-inch screen that holds all information...there's always the pop-up unit in the CTS