Assembled this today.
Question to aerohead:
Do you think I should trim down the "fins" so they end at the height of the spoiler's rear edge?
Here's view from the other side. You can see the artwork printed on the inner surface of the side panel, I got that one at a reduced price!
Did some AB testing. Results were definitely not as good as I'd hoped. Also, seeing a cop hanging out on my test route discouraged me from doing the final "A" part. The car has no cruise control so I just had to do my best to start each coast at the same speed. I attempted to pass a particular speed limit sign at 40 mph, simultaneously putting the clutch in and going into a coast. I recorded the speed at start of coast at the same location each time, and recorded the end speed as I later crossed the same road each time, after about a half mile coast.
Northbound test runs, with spoiler:
START - - - END - - DELTA (MPH)
41.3 - - - - 33.8 - - 7.5
40.0 - - - - 32.4 - - 7.6
Northbound test runs, without spoiler:
START - - - END - - DELTA (MPH)
38.3 - - - - 32.9 - - 5.4
40.7 - - - - 35.5 - - 5.2
40.9 - - - - 34.8 - - 6.1
These tests don't show the results I'd hoped for. Speed loss was more pronounced WITH the spoiler, not without!
Next time I have an opportunity to test the spoiler I'll attach it with 3M's no-residue heavy duty duct tape and take it on the interstate. I found two places where I should be able to do a decent high speed coast.