low beam headlights

I just ordered H-11 HID bulbs for my 07 tahoe.  I don't want to change the headlight, just the bulbs.  Can anyone tell me what is the correct way of getting these bulbs in?  Some people say loosen the bumper, some say the rubber flaps behind the headlights (which would require to take off the aircleaner on the right, and the windshield washer bottle on the left side.  If it is the bumper, which would make more sense, do you just loosen it or do you have to move it?
 
Thanks 

Welcome to Tahoe forum.  Check out this thread: http://www.chevroletforum.com/m_44164/tm.htm
 
Good luck w/ your mod.