Inline cooler is good for 5 degrees and maybe up to 10
Noss head is good for some as long as you don't raise the compression, raising the compression raises temps and will equalize whatever cooling your getting.
Coolant additive is an effective way to drop 40 or 50 degrees, that's with Engine Ice. I'd use Engine Ice only, as it cools much more efficiently than watter wetter.
Radiator, expensive, like 3 to 4 bones, however, it is by far the best way to get the temps down and in a hurry.
If your jetting is good and you really need to get the temps down, the inline cooler won't really help too much, Engine Ice can help some, but if it is a necessity, don't screw around, get a large radiator and fill it up with Engine Ice and you'll be as cool as the Fonz.