The 07 MC SS uses the FE2 and FE4 suspension trailing arms, I checked. Basically any upgrade from the stock is good, just make sure its a tubular design, if its the C channel type its just as weak as factory and should be upgraded. You can bend the factory one over a knee its so weak, tubular is the only way to go.

Couple threads on these in sticky format, pros and cons for the first, the best way to upgrade for the second (I found, Drunkie stickied)
http://www.grandprixforums.net/upgra...ion-39418.html
http://www.grandprixforums.net/want-...ook-73001.html
GMPP, UMI, ZZP, etc... make sure its tubular and within budget and you should be good.


As far as the rotors, I have been running the R1 Elines front and rear D/S. They look nice, but useful not very much. I wanted the look without breaking the bank and when I upgrade will consider the Premium line as they are slightly better. But the Elines work very well and I love mine, have heard some horror stories but its all hit and miss with some parts.
Most people will recommend blank rotors as they give a little more bite and don't eat up the pads as fast, but its really up to you. Just get some good pads to go with them and you should be good to go. Make sure you measure your rotors and compare to get the right ones, if you have the 07 MC SS dual calipers it should be using a 12" rotor, not the factory GP 11". So be certain.