In response to "fenixus" the wattage draw is determined by the bulb not by the connector.
If you hook up a 65W bulb to a 55w connector it will still draw 65W. Providing that the wire is not bottle necking the current flow by being too small of gauge, and that the wire thermally(insulation wont melt) can handle the increased current load. It should since its only an increase of 0.83 A from 4.53 A which is about a 18% increase in current at 12V.
I checked though and the wire gauge on my 93 Camry SE V6 is the same for both low and high beam bulbs therefore the low beam can handle a 65 W bulb without issue.
As for service life, that is determined by the bulb manufacturer there is no standard run time for bulbs. It comes down to filament wire gauge and gas composition inside the bulb, check with the bulb manufacturer in order to determine the bulbs average life time.
Just last night I did this mod, for my low-beams and modded the connector rather than the light since I didn't want to repeat the work for the next set of bulbs i put in. There are two plastic ridges down the center of the connector, I shaved them off with a brand new razor blade came off like butter took about 15 mins for both lights.
I'm running PIAA 9005 Extreme White Plus which is a 4000 kelvin bulb, I noticed a significant difference in light. I left the passenger side stock bulb in and replaced the driver side with the PIAA bulb and the light projected easily 40% further than the stock bulb, as well as spreading the light further laterally which aids with peripheral vision at night. It was also very white compared to the yellowish color of the stock bulb.
http://piaa.com/Bulbs/Bulbs-9000.html
The other benefit to running 9005's is that the top of the bulb is clear thereby projecting more light forward, I attribute this to the gain in light projection.