FYI..
Cleaning UIM and LIM is pretty easy IF you do it every 10,000 miles or so... Just did it about 2K miles ago and the brass secondary butterfies were only slightly discolored, UIM had only thin layer of grease ..carb cleaner easily removed the minor buildup. Head ports were clean...I have the secondary butterflies cracked about 2mm so that may help too.
This way, no need to pull LIM and minimal grease to wash into motor. Takes only about 1-1.5 hrs to do the whole job. Or you can wait until 50K miles and take 8 hrs..