cable guy really helped me out, once i removed all the throttle body housing, spark plugs were changed in about 20 mins. it took longer removing the throttle body and cleaning it than it did to change the plugs.
67 Mustang 390 - take tire off, fire up blue wrench (torch), smoke hole thru inner fender well in proper place, put socket on extension thru hole! YUP, that's the way we did it in the "old" days.!
i put the delco irridums in my silverado at about 105k, and i love them. i think i used every ratchet, every extension, the swivel, sometimes both 1/2" and 3/8" drive extensions at the same time lol, i had to get real creative to change them.
i know you already have it done, i just hoe the bosche plugs dont give you problems. i dont know about the newer gm's, but i know around my year models, they dont get along with chevy engines