I doubt that one can of TORCO and one bottle of NOS in 10K miles caused that. In fact, they look very similar to mine at 14K miles. I wonder if the orange/brown is the norm for Iridium plugs as I've seen several motors with plugs like that with no octane boosters used. My older 5.7 with copper plugs looks more traditional colored but my newer 5.7 and 6.4 look similar to yours.I decided I would switch to a 1 step colder NGK Iridium plug in my 2014 R/T. I was quite surprised to find that my car already had Iridium plugs from the factory.
My goal was the colder plug so I continued with the install. However, I was also surprised at the toll that the Torco Booster had taken on my factory plugs.
My plugs have 10000 miles on them and I have used ONE 32 oz bottle of Torco and ONE bottle NOS Race formula during those miles. The orange (magnesium) coating was much thicker than I expected it to be.
The factory Iridium plug is ILZFR5E-11.
I used NGK LFR6AIX-11 plugs and the car really seems to respond well to them. My ST knock seem to be reduced. I haven't been able to go WOT, but I haven't had any ST knock under part throttle.
Are you running a custom or 93 tune? Just curious as you mentioned ST KNK. Are you running a 180 stat and lowered fan settings? Just wondering if that could be in play as well.