So, I finally got some time to turn wrenches over the weekend (with the skinned knuckles to prove it). I installed new Sylvania SilverStar Ultra headlight bulbs (major improvement over stock halogen and a welcome change given I live in deer country). I also got around to replacing the cabin air filter (which was filthy) both engine air filters, also filthy after a year, and 4 of the 6 spark plugs.
Yeah, I got the passenger side bank done no problem and the forwardmost driver's side, but when I tried to remove the TB to get at the last 2 I found the lower right bolt on the TB to be stripped out. I'll be out there this weekend with every tool I can imagine to get it out without doing any damage (suggestions welcome) so I can replace the last two. I'll also replace all 4 TB bolts at the same time.
To get to the actual point of the thread though: what an improvement doing 2/3 of the plugs has made. The others were fouled to hell and back as suspected at 102K miles. Idle and acceleration are smooth, startup is much happier, and so far, so good on the whole stutter item.
Used Denso Twin Tip Iridiam plugs (Part #4712/IXEH22TT) which are OEM specs but half the price of the #3442/FXE22HR11 that came from the factory.