So I am considering going with the Stance coilovers, but I am wondering if anybody knows what else is needed for the G37; camber, toe, traction? Do I need to get all 3 links, or do I only need camber?

 

If you drop more than 1 1/2" you should get the whole F&R camber arm & rear toe kits, less drop than that and you should get it in spec w/ stock setup.

 

and how much would the set-up run with the coils plus the camber kit ?

 

THMotorsports has the complete SPC F&R camber/toe kit for $509, about the best price I've seen. I got mine there a while back for a bit more, great vendor too
SPC Front and Rear Combo INFINITI G37 2008 - 2011 72260 + 72130

So depending on what coils you buy just add $509 to the price, and if you aren't doing the install it'll run $300 or more for the labor to install the coils and camber/toe pieces, and another $100-125 for alignment.