The A3 RNS-E is for any year A3 that was sold in North America.
The A4 RNS-E is for all A4 / S4 / RS4 (B6 /B7 platform 2002-2007)

# GPS Antenna
# Plug and Play wiring harness
# Radio antenna adapter
# Code Card
# Navigation software

Features:
- it operates DVD maps of US and other countries
- plays audio and MP3 music from CD
- 2 slots for SD cards (MP3 files)
- 6,5" panoramic (16:9) swivel screen
And much more! I'm limited to 500 characters.
Thanks,
Brian Kohler