According to your Garage on Stangnet I see the following mods:
Suspension:
Tokico Premium Shocks/Struts
Eibach Sportline Springs
Pro3i C/C Plates
Custom Welded Full Lenth Subframe Connectors
HPM Mega Bite Jr. Upper Control Arms
HPM Mega Bite Jr. Lower Control Arms
Steeda Adjustable Rear Sway Bar
Steeda Strut Tower Brace
Steeda G-Trac Bar
I can not view your link to the Mods due to a firewall on this intrenet where I am but I assume you have the above.
If so, what characteristics does your Mustang have now? Does it have understeer / oversteer tendencies? If you put a bigger sway bar or solid links on the front it will increase understeer, but at the same time you may be able to adjust that out with your Steeda Adjustable Rear Sway Bar.
Sounds to me like you may be okay with what you have and maybe should hit that Auto-x as is and just see how it does. If you can determine what the car is doing that you don't want it doing (understeering / oversteering) then go from there.
Good luck and have fun!!