Might have to give it a try ....... I see Amazon has a similar one for a price close to $100 after shipping - Yikes !
It works. I have it. Water from the window runs down...hits it and the cohesion and adhesion factor of water causes it to stick to this "water spoiler" and it drips down the back into the channel around the trunk. Water no longer runs into the trunk when I open it ( while it's raining ). It also looks cool as it matches the contour of my Tesla provided OEM spoiler.
How would you ever know for sure? I haven't noticed any range degradation...as I travel the same route every day.
I installed yesterday and wanted to keep the car dry to ensure proper adhesion. This evening I tested it and it worked like a charm. No more water in the trunk! It guides the rain off to the sides where the gutter is wider and so water stays in it and drips down the sides of the rear tail lights. The unit I got was https://www.amazon.ca/gp/product/B07VDRCNZT/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1
Of course the ceramic coat/waxing is speeding up the water droplets this is what is made for. Since i've mine i've started having this problem, before i had no problem when opening "slowly"
I wonder if that little "spoiler" has any impact on the flow of air over the body versus it not being there?
The ones I have seen for sale so far, have been ABS with "carbon fiber texture" or "carbon fiber grain"........
FWIW, on my Model 3, which was both built and delivered in March of 2019, I don't see water getting into the trunk when the rain is light; however, when the rain is heavy, some does work its way into the trunk. Before purchasing my car, I'd seen videos about the problem and so I did the same as you -- I bought an all-season weather mat for the trunk. Of course, that won't keep water off my groceries (or whatever I put in the trunk), but I figured it would reduce the risk of mold growing on the trunk's carpet.
My model 3 is a November 2019 build and has this problem. So if they "fixed" it then only partially. I do have a ceramic coating. (as a side note, I think a ceramic coating also makes your wipers much less needed, something the auto and built in speeds for the wiper do not accommodate well!) I had been watching this one on Amazon. Has more reviews than the other amazon one posted above. Seems a bit steep in price. But it is a bit annoying. The most annoying part is more that others see it and crap on the car! And they aren't exactly wrong. https://www.amazon.com/WJM-Tesla-Window-Spoiler-Retaining/dp/B07ZVGHB17/ref=sr_1_2?keywords=model+3+trunk+water&qid=1578682653&sr=8-2
I see this comment made every so often but don’t find it valid. Tesla sells and tests their cars around the world. They do make part changes all the time.
