I have yet to take delivery of my 2006 performance white GT (it was built this Monday), but I have read a lot about Mustang specific arms and know a thing or two about suspension design.
Some of the more popular aftermarket arms include products from Metco, Steeda, BMR, and Spohn. In addition to tubular arms similar to those offered by BMR and Sohn, Metco and Steeda offer the billet arms as well. Although I do not know about the relative strengths of the aftermarket arms compared to one another, all of the products offered by these suppliers appear to be far more robustly constructed than the stock pieces. Also, the tubular pieces are lighter than the stock pieces. I am sure that the machined aluminum arms are even lighter than the tubular arms, but by how much I don't know. My suspicion is that the little weight difference is relatively insignificant on a street driven car. Not only are the tubular arms lighter than stock, as previously mentioned, they offer adjustability that billet arms do not, at least to my knowledge.
Having driven the 05+ only three times, none of which I did a standing start drop-clutch drag launch, I cannot comment on the stock wheel hop, though practically every post that I have read indicates that aftermarket lower control arms in combination with an aftermarket upper control arm eliminates wheel hop altogether.
By the way, I see that your screename is Baylor 2010. Are you in the Waco area?