To wing, or not to wing... that is the question
So the car needs dimples then?
I suppose I'll try to remember to leave mine out during the next hailstorm.
We already have dimples on the first versions of the Spyder. I eliminated them with a product I use to sell called the de-dimplator. Not one wrecked Spyder because of it but it does make me wonder if they actually did something. Probably someone at Toyota thought it would look cute. Thankfully the facelift did away with that ugliness.
I could tell a difference after I had a wing on my green spyder with side winds and the effects of the wash from passing/meeting semi trucks. Below 40ish MPH, it didn't make a difference, but as you get closer to interstate speeds, you can feel it, over interstate speeds, there's a definite undeniable improvement. I doubt a duckbill or the small trd wings do much. The TRD style like was offered on the Celica GTS might add some stability from crosswinds though. You really need to drive a spyder with and without a rear wing and get hands on experience before dismissing it.
If weight alone was the deciding factor for crosswinds, then semi trucks and loaded trailers would be the most stable in crosswinds, they definitely aren't(majorly due to side surface area). Also, my BRZ is more stable than the F-150 4 door short bed pickup or the F-250 four door short bed pickup I've driven a lot. My BRZ feels more planted in crosswinds than any of my spyders, but I also have a lot wider tires on the BRZ (255 vs 205) Even if weight was the only factor, then a wing will still help as it artificially adds weight to the car in the form of downforce. Weight does play a role, but aero plays just as an important, if not more important role than weight.
My Ford Flex doesn't get pushed around by crosswinds like the Spyder does, and it's nothing but vertical surfaces. It sure is heavy as hell... holds a few more people though.