I didn't put them on for a brighter light really. I put them on for a whiter light. With my stock bulbs, i would get out at night and look at my GT and the lights would appear yellow. It looked kinda ugly if you ask me.
The silverstars look white when you look at the car at night. It's a cleaner look. They do toss out a bit more light, but it's more of an appearance thing to me.
I'm just waiting til the new 893 fog light bulbs come out to finish off my look.