I've heard horror stories of aftermarket bulbs melting the lens because it is such a small area inside the lens itself. Most of the time it's because people put the wrong wattage in or HID's. My question is even if I get the same wattage fog bulbs, but upgrade to Sylvania Sivlerstar's, will it still have the same effect? I'm sure they since they are whiter light that they burn a little bit hotter. If not I guess I'll try LED's.
As long as you stick with the same wattage, you should be fine. LED style bulbs will also run much cooler, and prevent any chances of melting the housing if you elect to go that route as well. Different brand HID's will run at different temperatures, but I have ran 35 watt HID's before in these with no issues. It's when you go up to 55 watt where they will run way too hot.