However I read a few BBS entries that said it doesn't?

I have never read a BBS entry that said the ethernet port is disabled in the car.

I have read BBS entries which said the following:

1) The serial port runs only at 4800bps in the car, and the flash upgrader does not work in the car. This is the serial port, not the ethernet port. And this is in the FAQ.

2) Many wireless ethernet bridge devices require special power requirements other than 12v, and sometimes you need to do special things to get them working in the car. This is not the empeg player itself, but rather, the third-party wireless bridge.

The FAQ entry on docked ethernet is here, and the FAQ entry on wireless ethernet is here.