For what it's worth, I have experienced the spark knock with my 11 as well. I first installed the FRPP tune around the end of May, about a month after I purchased the car. However, it never once did it until after I took it on a 1400 mile road trip up to Illinois and back.
It was very noticeable, and it happened whenever I gave it more than half pedal anywhere from 2000 rpm and up. I tried setting the octane adjustment to Y, but it didn't help much. At first I blamed it on crappy gas, but it continued even after I had run several tanks of top tier 93 octane through it.
I went back to the stock tune for a while, and although it ran as expected, I really missed the utterly superior performance (IMO) of the FRPP tune. Additionally, having the skip-shift back drove me crazy, and my fuel mileage suffered noticeably.
I have since put the FRPP tune back on the car, and it seems a lot better. It only does it lightly at the rpm that others have noted now. It seems like the cooler weather we have had recently in N GA has made a big difference for the better as well.
Just wanted to put my experience out there as well, since I've been following what everyone else has posted on the subject, but have yet to contribute anything useful to anyone in return.
2011 GT Coupe Premium / MT82 / 3.31 / Brembo
Red Candy Metallic / Charcoal Black / 400A
Comfort / Security / HID Headlamps
FRPP M-FR1-MGTB Power Upgrade Package