From Daniel Stearn (headlight professional):
Your low beams take a 1350-lumen H11 bulb. You can easily, safely, and effectively replace this with a 2100-lumen H9 bulb, which you ought to be able to find locally by seeking the high beam bulb for a 2008 Chevrolet Malibu. Use a good brand (GE, Philips, Osram-Sylvania) and stick to colorless clear bulbs, not any kind of "whiter light" bulb such as the Sylvania Silver Star scam. You may need to shave a small ridge of plastic off the H9 bulb's connector so that the H11 socket will snap on. Other than that, it's a direct swap. The only disadvantage is shorter low beam bulb life — the H11 is optimised for very long life with relatively modest light output, while the H9 is optimised for very high output with relatively short life. Note that the H9 swap is not universal; it works well in projector-type low beams but is not safe in most reflector-type low beams or in fog lamps of any type.
If you want to upgrade the high beams, go to your local Chevrolet dealer (or
GM Parts Direct: Your direct source for Genuine GM Parts for a better price)and pick up two part number 15094219. That is a 9011 bulb. They are not some tinted or overwattage version of 9005, but share the identical filament geometry and base architecture as well as the same power consumption.
Here's the comparison:
stock: 9005, 12.8V, 65W, 1700 lumens, 320 hours
new: 9011, 12.8V, 65W, 2530 lumens, 320 hours
The 9011 bulbs have a double-wide top ear on the plastic bulb base, this is
to comply with the law requiring different bulbs to have different bases.
The extra-wide plastic top ear is easily trimmed or filed to make the bulb
fit your headlamp's bulb receptacle. Once that's done, they go directly
into the headlamp, and the existing sockets snap on. Please see
HIR bulb base modification for details.
Note- This was for my 06. Check your headlights. I don't know what the 03 has.
