At 100,750 miles, I finally changed out the spark plugs, (Iridium IX) and coils (Blue Streek) on my 16RT. The dealer made it sound like it was a hard job, but then again that is how they wanted to justify $1,200 for the cost of replacement.
I was prepared for a long fight with the D, but with a standard 3/8 socket set, and it took under 2 hours. Not a single cuss word was said. The parts cost $301 from Rock Auto. My only regret was that I didn't get the Ruthenium HX plugs, which only cost a small bit more. So, I get to do most of this all over again in the next 2 years, as the IX are 40-50K plugs.
Long story short, the plug replacement on a 16 RT (16 plugs) for this left-handed fella wasn't hard at all. Best of all, I saved I about 900 bucks.