What is the standard (i.e. factory) sound system installed in a 2003 G35 sedan? I've
read several reviews and all of them say that they're testing the car
with an optional Bose in-dash 6-CD changer. But l have not found a G35
sedan from that year that *does not* have this sound system.
Is the Bose in-dash 6-CD changer optional or standard?
Thanks.

Nearly all of them have the Bose system. So l guess you could call it standard? There are a few out there without the Bose, but they sound very close to the same quality. If you get one be very careful when removing and installing cd's. Wait until it tells you to insert or jamming can occur. They do not like cheap or dirty burned cd is either.

According to edmunds.com the standard sound system is not a Bose. However, many of them do come with it as an option. Here is a link to all the standard features of the 2003 Infiniti G35 sedan: http://edmunds.com/used/2003/infiniti/g35/100217714/standard.html

The Bose in-dash 6-CD changer optional.
Steering Wheel Radio Controls
Audio / Video
Bose System
AM/FM
Cassette
CD Changer
7 Speaker System
Premium Sound
Separate Tweeters

Most infiniti dealers ordered cars with Bose because you also loose that HID headlights and sunroof if you do not have the premium package.

The base G35 sedan has always featured a non-bose system. It sounds pretty good , but not like a bose. All G35 is with the Premium Package (probably over 85% of those built) have the bose system. FYI, this information also applies to the G35 Coupe. Hope this helps.