I haven't had to change a headlight bulb yet, but I feel that the high beams are exceptionally good, too! If your high beams are not much brighter than you low beams, something else is definitely wrong.
If your car is relatively new (less than one year of ownership & 12,000 miles) any good Mitsubishi dealership will take care of this for free. When I went in for my air bag recall last summer, they didn't even have me get out of my car until the a service person checked all my lights. My third brake light was out (found out it became unplugged), & I didn't even realize it. They simply took care of it while doing the other free service.