Glad I didn't tune my 13 SHO PP yet. The car has 103k miles and just realized I still have 300 miles left on my base care warranty so hoping it can be sorted out. I have owned the car since 79k miles and I have never tuned the car. Car seems to shift fine during normal operations but when I'm doing about 40+ and I floor it to where the trans kicks down, it downshifts no problem but right after it does, it does some kind of weird shudder/slip and then continues on accelerating. I tried at 40mph, freeway speeds, tc off/on and still does it. Going to take it to dealer this week to see if they can figure out.