Are their any good Suspension Handling/Performance Upgrades for the 07 MCSS out there? Sway Bars? Struts? Springs?

 

All of the parts mentioned are available, but there isnt much variety out there. The other downside is that even if you bought everything, handling is still limited by being a relatively heavy FWD car with narrow tires.

I think the biggest bang for the buck are sways (GMPP or ZZP) and coilovers with good adjustable struts. I wouldn't personally spend the extra money again on all the poly bushings / bigger rods for the rear / etc.

The other thing to consider are your tires as those will have almost as much impact as all of the suspension mods combined if you just swap from economy tires to a high performance tire.