DO NOT put HIDs in the stock housings in an ALH.
You WILL blind oncoming drivers. Those are NOT projectors, which can focus the light properly. Yes, you will see better. The spill, however, will blind the guy coming toward you and he may hit you head-on as a consequence. There is no way to put an HID bulb in a reflector housing and have it properly pattern the light.
Oh by the way, if that happens and you live you're screwed as the accident will be ruled your fault.
BTW the "silverstar" and similar lamps are garbage in terms of actual light output. They get the "more blue" color by filtering part of the spectrum, which actually REDUCES lumens on the road! That's the oppose of what you want. In addition the human eye is best sensitive (in terms of detecting things in the road and around it) with slightly-yellow colored lighting, NOT "pure white" and DEFINITELY not blue. For projector H11s you CAN use an H9 bulb with minor modifications to the bulb (easily done in 2 minutes with a Dremel) which is a LOT brighter, and since it's a projector you won't blast the oncoming driver. The trade-off is (materially) shorter bulb life.
But there's no way to do that with the combined-filament reflector headlights found in cars like the ALH. There your best bet is going to be a higher-output (shorter life though) UNFILTERED (look for CLEAR glass on the bulb, NO COLOR TO IT AT ALL) regular bulb. Again, the price you'll pay is shorter bulb life and on the ALH cars you want to disable the DRLs if you do this or you'll probably be real unhappy with how often you have to change them.