Sylvania probably makes a Silverstar replacement. The GT bulbs are H10's, and I *think* the GT/CS bulbs are H11. Verify the bulb type, and go to your local auto parts store and look for the appropriate silverstar replacement.
I use to due this on my integra back in the day:bigthumbsup. I think they don't last very long because they get hot, I have no proof, other than gut feeling.With a very slight modification, you can install an H9 bulb in place of the H11. The only difference is an extra locator tab in the bulb connector. Just trim off the extra tab (circled in red) and the H11 connector will plug right on.
An H9 bulb produces 2100 lumen compared with an H11 bulb's 1350 lumen - that's 55% more light. The trade off is that H9 bulbs don't last as long as H11 bulbs.
I just got a set of Silverstar Ultras for my headlights. I didnt see anything for the CS fogs, only for the grille mounted ones. Maybe I just missed them? Idk, ill have to check again and see.I'd get a set of Sylvania Silverstar Ultras. That's what I have in my fogs, and they're nice. Not HID nice, but brighter and whiter than stock.