Do the aftermarket billet control arms provide any substantial benefit over the stock arms or is it negligible? I'm looking at getting the Sinister Mustang arms, but that's some $$$ if there's not much performance improvement.

 

I think it will add some benefit but will you feel it with normal daily driving? Probably not so much. Now if you changed uca, lca's, some springs, shocks and panhard all at the same time you would notice that for sure. Save your cash for something else. If not I have a set of these and they came highly recommended by another vendor that sells their own parts.
http://www.blowbyracing.com/bbr-0506-001.html

 

Cars modded and I drive it like I stole it. Pushing around 450+. Xcharger Xtreme, full suspension mod(except upgraded RLCA), Stage 2 clutch, aluminum racing flywheel and driveshaft, tuned, 3.73 gears, lowered, sway bars, etc. Squared up. Wife just bought a MGW shifter for me for Fathers Day. Just trying to make time to install it. With those mods, will upgraded arms make a difference?