As for the difference between solid vs hollow sway bars, I don't know the actual differences... the solid probably is a little stiffer. I've read somewhere that the hollow bar's main strength comes from the OD radial wall thickness... in other words the center of the bar (solid) doesn't have that much effect... its the OD wall thickness that matters the most.

IF I don't like the results of the hollow front sway bar, I'll put the solid bar back in.... probably a few exchanges will be needed for testing/comparison to make any conclusion. I do favor the weight reduction an important overall factor for the car's intentions of usage.