So I retested the spoiler today. From today's results it's a wash. Avg mpg 34.87 vs. 34.89, or about .05% difference. Now I was putting the spoiler in the trunk, so if you actually removed it from the vehice you might see larger gains because it weighs maybe 3lbs :P
update 9-8-12 finally decided to take off the spoiler after seeing arcosine's tuft test
http://ecomodder.com/forum/showthrea...p-22429-8.html