H9 bulb mod (link in my signature below) gives about 150% more light than stock. 35w HID kit gives about 2 to 3x more light (depending on bulb color temperature). Our Prius has the H9 bulb upgrade, which is pretty good due to the nominal voltage of 14.4v that the Prius operates at. H9 bulb upgrade can be done for under $20 for a pair of quality name brand German made bulbs (Philips/Osram). My Camry has a 35w AC HID kit (5000k) with blocked squirrel finder cutouts.
