I made up one of these. Clamped it under the nose and DANNGGG, it was massive. Definelty looks different on a street car. I was going to trim it down and make it smaller, but it wasn't long after making it that I left the employ of the place that had the shears and brakes to make it easy to modify. I've still got it around, still haven't changed its size, nor mounted it. I think I've got some pictures somewhere I'll try to find.
I did use an MAS universal fiberglass piece for a while, which is a much smaller unit and looks like a '69 Mustang piece. Even in its reduced size it was signifcantly lower than the valance and required attention to dips while driving. I scuffed it numerous times just tooling aorund town, but, my car does sit looooww compared to most.
Everyone will think it's some homemade job.
...and Posey's wasn't? It sure has heck didn't come from the factory with that on it. FWIW, there was a guy on Moparts who tooled up a bunch of ABS replicas of the AAR race spoiler. He was going to do Challenger versions but never got enough deposits to make it happen. If someone wanted a large, race type, "factory" appearing spoiler for a TA, I imagine you could throw enough money at the guy to resurect the project. I think we has asking $200 each with a minimum run of 10 pieces. Heck, I think he still has a couple Cuda versions left you could buy and cut turn signaa clearance in to.