I'm not a fan of spoilers on the 67 - 69 Darts but hey, it's your car. Did you install it for merely cosmetic purposes or was it for functionality? I'd spend my money elsewhere instead of that little piece of plastic.
I installed it for looks only, im not sure on the benefits of downforce it would provide for racing or driving. I wanted something to hide the bottom of radiator area while breaking up all the "bling" of the bumper.
The 160 for the spoiler and the ride is like throwing a rock into the ocean for as far as cost to build the rest of it. I was happy to buy something for under 200$ for a change.
