I have done a good bit of research on this.
I have Silverstars in my '03 Cobra. A nice upgrade. I even went to the Silverstar 9005s as opposed to the factory 9145s...BIG difference.
I also put a set in my G/Fs Jetta...she is very pleased.
Like many other newer Fords, my '05 Excursion uses a new bulb, the H13 or 9008. These are not made as Silverstars as DOT regulations will not allow a coated bulb.
As far as an import Silverstar or the like....all they can do is throw more light. The light pattern will not change as that is decided by the lense. The actual light pattern, cut-off, etc, is not affected by a bulb. In older cars with the round or rectangular replacement bulbs, there could be a difference, especially when changing to a Euro spec lamp.
There are many companies that make bulbs you may see in stores or on ebay. Some claim to make XX watts of light while using no more power than your standard bulb. BS. To make more light, you must consume more power. A slight increase in perceived light is possible, like Xtravisions, by moving the filament...but not a double increase. These bulbs can be the cause of your wiring harness melting or burning as it was not designed for that much of a load. The formula for figuring out how much power a bulb will use is to divide the rated wattage of the bulb by the voltage. For example, a 60W 12V bulb would require 5A of power.
Xtravisions were also mentioned. According to Sylvania, Xtravisions offer the same "brightness" as Silverstars, but at the standard halogen color. This works by not adding wattage, but by adjusting the relationship of the filament in the bulb itself.
Finally, HIDs. Unless equipped from the factory..switching to an HID set-up is completley illegal. In most states, you won't even pass inspection.