OK...I take it back. I had the Cobb RMM off the car and my OEM battery back in for a dealer visit. Now that I put that stuff back on and have driven in low gears, I'm convinced I can feel a noticeable difference from the wheel weight.
Frankly the car is pretty damned impressive on the street with my weight under 2700lbs and the light wheels plus Cobb RMM traction improvement. Almost...almost has me satisfied with the stock power but I know a pro-tune and intercooler will be mind blowing.
Also, a better shot out of the blazing sunlight: