My fabricated units are made from .040 aluminum.
The MAS spoiler is a generic, inexpensive, fiberglass piece. Their front spoiler is not specific to Cuda or Challengers, or any thing except maybe Camaros or Mustangs. You will get the same unit if you buy one for an E body, or F body, or Maverick, or Gremlin. In my view, their front spoiler is a slightly larger version of the 1st gen Camaro or 2nd gen Mustang chin spoiler.
Most the issue I've read of with MAS products is from persons who thought they were getting a fully fitted, custom made, restoration quality, ready to bolt on piece comparable to other high end fiberglass manufacturers. This is not the case. If you want a budget piece and don't mind working on it some to get the fit and finish you want, MAS is a bargain. It will not fit precisely to the contours of a lot of cars, but is close enough to look okay. Because Challengers have turn signal pods under the bumper, it does create a varition on contour that will impact fitting of this unit compared to a Cuda. So, how well you like it is subject to personal interpretation.
Another alterantive is to buy the Cuda AAR race piece and adapt it to fit. However, instead of cutting up or modifying the $60 unit you pay to MAS for their generic spoiler, you will be paying $200+ for a cuda peice that WILL require modifications to fit under a Challenger. For a roll of the dice that achieves the same results, I'd rather loose $60 than $200 if I was unhappy with the finished product, but I'm a cheapskate.
The factory style TA chin units may be your best option. They fit the Challenger valance specifically, they mount in a factory arrangement, they look good without being intrusive, and they are moderetely effective. However, like I said above, don't get the MAS versions if you expect a factory duplicate. They make inexpensive, workable pieces and do not make finished to factory spec restoration parts.
It does sound like there is a business opportunity in here if someone was so inclined.
The effort & cost of custom fitting the MAS piece should be no greater than making your own & in the end would probably be considerably less effort. 
This is the truth. Fitting up my fabricated units has been a fair amount of work. Without a large shear to cleanly cut peices of aluminum, most home efforts may end up looking pretty cobbled. Trimming four feet of sheet stock with hand snips ain't going to get it. Glassing in a steel mounting strip and a couple of brackets on the MAS unit would be easy by comparison. Personally, I wanted something bigger and more competition inspired than the MAS piece which is why I am making my own. Plus at the time I worked in a sheet metal shop so all the material was free and I had access to the large shears and brakes to make clean cuts and crisp bends. Since I have them now, all I have to do is refine them for the look I want.
