The G35 coupe Tail lights are different, the older models have one LED ring in the back and LED bulbs than run across the sides while the newer 05-07 models have dual LED Infiniti Signiture rings giving it a more modern look, that can always be changed and upgraded or modified if you choose to purchase an older model. Horse Power is also different from the years 03-07. A 2003-2004 G35 coupe produces 280 HP while a 2005-2007 can produce 298 HP. Options and interior quality changes through out the years 2003-2007. There are some few minor upgrades. The 2005-2007 Infiniti G35 seem to get XENON Headlights (white lights),most of them have them, the 2003-2004 have halogen yellow headlights but remember you can always upgrade, modify or order factory Infiniti Xenon headlights for older models. The Rims are also different on the 2003, they look a little old while the 2005-2007 have more spokes and it looks a bit refreshed opposed to the older versions.