Yeah a median figure might be better than the average. I originally suggested an average column, but that Bugatti Beyron really throws off the averages.
Also
www.edmunds.com is a very good site for this kind of information to double check or do a quality assesment of your stats.
For instance the heaviest 350Z I could find weighs 3404 lbs.
Also I've never seen a GTO MSRP for less than $30K, unless they included factory rebates or dealer incentives.
http://www.pontiac.com/gto/index.jsp
That is part of the reason I didn't get GTO....:( but I digress.
I apologize for the nitpicking, this is a great spreadsheet and I love looking at raw data numbers like this. Great job. I think this would be worth making a sticky.