Check out the January 2006 issue of Consumer Reports, page 47. They did a comparison of replacement headlight bulbs. They tested using the OE bulbs, Arc Plasma Ultra White, GE Nighthawk, Philips Crystalvision, Sylvania Silverstar, and Wagner Truview in three different vehicles (Honda Ridgeline, Chrylser Sebring, and Toyota Camry). Results varied depending on vehicle, but only the GE Nighthawk in the Ridgeline improved low-beam distance. Yet, the same brand reduced distance in the Camry.

I recently installed the wiring harness 4Crawler sells and it made a very noticable difference with Sylvania XtraVisions I had on the truck. I now have the e-spec Hella Vision Plus lights with Hella Xenon +30 bulbs. The "brightness" did not increase dramatically (in my opinion). But, what is noticable is the light pattern is more consistant across the the road vs. the XtraVision tended to have hotspots.