Everyone says that the AMD parts are better than Goodmarks. I know that at least some of Goodmarks parts are made of a thinner gauge than origonal and that AMD's are the correct gauge. That said...I have Goodmark full quarters, rear valence, front fenders, as well as a few other structural brackets on my Challenger.
The quarters needed some work in the gas fill area. There is also a small raised section in the bodyline that needed to be straightened near the side marker. The side marker fit really well when I test fit it. The mounting holes may just need to be opened up slightly for the lense to be perfect.
The front fenders needed a lot more work to fit. The lower bodyline was off by roughly a 1/2" and required the fender to be cut so the lines would match. The hood was about a 1/4" higher than the fenders also. The fenders were cut along the top and moved up...in-line with the hood.
I don't know when AMD is supposed to have their front fenders available but the talk is that they are going to be a lot better than Goodmark.