There is plenty of good advice here. Bottom line at least a front BBK will be safer and quite possibly pay for itself if you track enough.
An above poster mentioned his experience in an intermediate/advanced group. That description is correct if you are in a group where you wait on slower cars/allow the brakes to cool. Once you are able to push the car lap after lap (lack of slower cars) the oem brakes will become an issue. Cool ducts might help but will not solve the problem.