How much is too much?
Depends on your reference really. How far you want to go, what you want out of a system.
Sound quality people with a critical ear and want sound quality know what it is and want it in all there systems is a dyeing breed,
I would say myself the Ipod is more or less the last nail in the coffin.
I build and test reference home audio equipment everyday so i have a very high reference to work too, i also have a very expensive home system as another reference, any standard car system sounds like im listening through 3 pillows to a scratchy gramophone playing to me so i HAVE to go after-market as any standard or even OEM option is simply not good enough and drives me crazy with it lack of tonality, detail, ambience, imaging and staging.
Most people don't even have a clue what can actually be achieved in a car in audio terms. They simply write it off as a hostile place for audio, which it is but quite a few things can be compensated or changed to get round quite a few of the objects to audio in the car. At the end of the day your home is also a hostile place for audio if you look at it from an audio point of view you have many hard reflective objects and soft absorption surfaces as an example walls, glass, furniture, floors etc.
This is why i always recommend to people get along to a sound quality soundoff and get to hear some of the top cars in each class don't just dismiss car audio as never been anywere near as good, Go along and get to hear what you can get a car to sound like. It often astounds people how good it can be, and how near to home audio.
