Welcome to EBPF snaf2u!!
Glad to have you aboard!Got the mod bug already... lock up your wallet!

I gotta echo SHOdded... get with LMS and get the v8 tune.
At least go to 4+ which is the most similar to v8in the previous series of LMS tunes... you could easily trim .2-.3 sec off your time with either change.

I have no hesitation or noticeable turbo lag with v8 in my '13 SHO....
Add the 3BAR MAP (easy and cheap 5 min mod) and the LMS tune adjustment (free) for it you'll find the tune even better, likely because gives you a whole new and improved turbo mapping ...as well as a few more tweaks. I love it in my '13 non-PP SHO.
I'd stay with the tune for the octane your running though... likely that's why you probably got knock (predetonation) and so hesitation due to ECU safety factors intervening (pulling timing) to save your engine. I hate AZ gas at 91 too!
Please put up an introduction post in the new member area and tell us a bit about yourself... TIA