Quoted from Burley9043:I have always purchased the UV Glow for my machines and have been very happy with it. Scott will tell you it is the most popular and I would recommend it. You need the GI module. Though they say the Invisible-Shield is recommended, it is really a preference. I don't have it on my Shadow because they were not available when I bought the lights, but I bought them for my Iron Maiden. You should check out some videos to see the difference.
I recommend Pinstadium+Invis-Shield for Shadow. The ability to tint white, red, or blue is really nice.
I tried the UV Glow flashers and they are neat, but I disabled them. Too much flash for me personally.