What’s the best way to install low beam Bulbs? Or only option is to remove the headlight assembly?

you don't have to remove the assembly on the 04-06, you should be able to squeeze in after removing the air box on the passenger side or the fuse box on the driver side

Nope, videos on YouTube show the longest way to do the job. Passenger side has most access from inside area, it took me 10 min to replace the bulb. The driver side might be problematic, especially if the lid is dead closed. It took me an hour to use the right tool to rotate it.

Only thing I had to remove is four-five bolts holding fuse boxes on driver side, then push one of them aside to clear the space.

There is a fuse box, left side, that you unscrew and sort of twist out of the way. Then you have working room to change the bulb. Note, that you have to go by "feel", as it's kind of difficult to get a visual on the bulb socket etc. The right side is pretty straight forward, take off the plastic covers, reach in and twist the cap - un-do securing hook - twist bulb out .. again sort have to go by feel, but it's not as difficult as it seems.

Yeah, I didn't do this myself so can't specifically say what they did, but I was getting other work done by my mechanic and went to pick it up, saw that I forgot to ask him about doing the headlights with the new bulbs i had bought and left in the glove compartment. Apologized and asked if he could still do it, five minutes later it was done. I wasn't watching closely, but they did not remove the full housing.