I PM you back, but....
Only real difference between the two will be the FKS is metal, and will last longer.
If you are considereing the FKS 120 then the higher din capacity of the race stocks is not an issue.
The toe and heal piece are different, but the two bindings will both release when they need to. Both bindings are good. I agree that the race stocks are better, but whether or not the difference between the two bindings will be worth spending extra money is kind of iffy....particularly for a 120.
So, if you are extremely hard on bindings in some way maybe get the FKS 120. They will last forever. If weight is an issue remember they are slightly heavier than normal bindings (I dont care, some people do).