Painted rear axle by me in 2006, for the price Ford charges for the Mustang you would think they could paint the rear axle and brackets, they paint everything else under there!!
I first put the Ford Racing SVT lowers on (these are the ones on the GT500) still had the wheel hop, put the BMR upper with new mount on, no wheel hop, LMPerformane is where I bought the upper BMR+mount. also many be on ebay or amazon seems to have the best prices on most things.
to eliminate the wheel hop you need to change the upper control arm and brace, I went through the same thing, the stock brace is flimsy, I used the BMR adj.and brace, you my not need the adj. one, unless you go with the alum drive shaft.
Ford Racing SVT lower control arms have stiffer rubber bushings, I have these on mine. The BMR arms may use the poly bushing that give more vibration. Punch in 2012 mustang lower control arms on Ebay. What are you trying to accomplish?, do you have wheel hop problems?
I went with SVT lowers and BMR adjustable upper with BMR upper bracket (stock bracket is flimsy) not easy to install but this took care of my wheel hop, if that's your problem, (note) if you use to much poly. you get vibration you don't want. good luck.
I did mine myself, hardest thing I did on this car, (and I put the Supercharger in) has to be done just right, with special tools and gauges, a ford dealer gave me a price of $800 labor, I would charge $2000 it was a bitch!!! Some say they got it done for $250, I would think $500 to be average...