the problem with cars these days is that most if not all of the decent cars have this whole system of integration built right into it, so the nav is linked in with the stereo - and the 6 dics changer is all integrated into the dash, so getting something aftermarket is kinda touchy without going to whole custom route....
I looked at it for my new Honda Accord, but its got all the NAV and everything in a cluster, even trying to go with different speakers is a serious pain as you have to get outboard crossovers, and amps and likely an EQ system to straighten things out. I just said - ahhhh its good enough for my car...
I'm pretty sure the JBL MS-8 would let you work that out... that's one of the reasons its such a valuable processor.
You could use your stock CD Player and wire its RCA outs straight to the JBL Processor which you can install in your trunk or underneath your seat or wherever else AFAIK if the dash isn't the right spot for it.
1) Active Crossover - It's an outbound crossover that sets everything up for itself with a microphone.. REALLY WELL. It can do as much as a 4-way (T/M/W/SW) and people I've seen have been more impressed with its auto-crossover than even tuning it themselves for long times with their Audison Bit-Ones
2) EQ - It uses Harman/Kardon's logic7 room EQ system for your car but also has lots of GEQ (and IIRC PEQ) resolution. Many people have been
very impressed with their results, from what i've seen moreso than car implementations of Audessey (Alpine's imprint).
3) Surround sound - in order to get good stereo imaging in car given seating restrictions, it allows you to use a center channel IIRC. It's not necssary, and you can stick with 2 channels in the front and a sub in the back but people have had very good results with this as well.
It really seems to be a Harman version of the DEQX... and while we may think $800 MSRP is expensive.. it's really chump change next to the HT equivalents for all its functions.
Yes you (er.. I) would need to get amps, 6 or 8 channels worth most likely. And drivers and install it all. That's where I'd like to see actual.. ya know.. measurements, results, etc on the right amplifiers.
The other most important thing would be deadening to eliminate rattles.