I am trading in my 2003 Q45 tomorrow. It is not because I don't like the car, I love the car. Becuase my wife totalled her Frontier, I needed to get a truck, so I traded the Q on a Titan LE.
The Q was the best car I ever had. So many features, it blows people away. The best things were the rear view camera, the auto trunk lid up/down, the front cooled seats, and the NAVI.
The two bad things about the Q are 1) It really sucks in the snow (RWD), and 2) The resale value is bad. My dealer said that they are selling new 2004 Q45's at almost $10K off of list. This may have been bull, but when I bought my Premium model, I got almost $7K off of list.
I don't know why, as this car has so much going for it. It makes no sense that it is undervalued like it is. I don't think you can get as much car from any other manufacturer for the price.
The 2005's are on the Infifnity website, but there are not that many differences. I think the 2006 will be a big change.
Don't be afraid of getting a Q, just get the best deal. That will help you when you trade it in on a 2007!!
:-jon