No, nothing too permanent. I could have the whole thing off in 5 minutes, and not really leave a trace that it was there. I don't know of any areas to watch out for heat-wise besides the exhaust.
I'll be watching mileage to see if it improves. The true test is a highway trip with the family, which means 70mph and A/C on. We should have one of those in the next couple of months.
I will probably leave the air dam off until after that trip and see what we get. In spite of the coast-down results, I remain suspicious of the air dam's efficacy. It has not lowered my mileage, though, and it improves the car's stability at speed, especially in crosswinds, so maybe it is worth it. Some people would say that having the belly pan means I don't need the air dam... We'll see.
For me, it is the right combination of stiffness and ease of cutting. Coroplast cuts very easily with a box cutter, more easily than cardboard even. Even aluminum flashing would be more difficut to cut. And if I were able to get a big sheet of aluminum the same thickness as flashing, it would be realllly floppy and would cut me to ribbons. :-)
Coroplast is lightweight compared to aluminum of the same stiffness, as well.
AND, lastly, after elections, the big coroplast signs are litter, and I like to help the candidates clean up their mess, because I'm just sweet like that. :-) What I'm saying is that coroplast is free if you are patient. A sheet of aluminum could be sort of expensive.
So for me it is the right combination of physical properties and price. Maybe you are able to get AL for really cheap, in which case, AL might be the right choice for you.
Nice work on the underside of the element! Coroplast is the way to go for best bang for the buck! I've had mine on for about 10 months, 5 of them in MN winter weather! It holds up extremely well! Ok, enough exclamation points for me now, lol.
Got another coroplast source for you. My city, like many others has restrictions on off-site signs. Our public works guys are always collecting outlaw signs from the right-of-way and other prohibited places. They wind up in a trash bin. You might call your city and see what they do with illegal signs.
I paid the $$ because I wasn't willing to wait for Election Day. Of course this year I'll be ready and will collect what I can.
This was kind of funny. There was only one candidate who put up a noticeable number of 4'x8' signs. The election came and went, and I put my wire cutters in the car, planning to help him clean up his litter. But, just to make sure, I looked him up and looked at his website. Turns out there was a run-off! So I had to wait another couple of weeks before I helped him.
Graeme, I need to go by the local plastics recycling place and see if they have some too. Good idea about checking with the city.