Momo,
I've been using a Bama tune since I purchased my GT in 2017. Very general mods applied. Borla Touring Cat-Back Exhaust and Airaid CAI. I'm running daily on the 93 octane performance tune. Definite hp increase noticed mainly at upper end. Overall it was worth the purchase for the first mod. Concerns have been with shifting which seems hard for this automatic. Paddle shifting is nice as you can let it rev higher into the next gear. The most annoying aspect of this tune is casual driving with the air conditioner on. The car seems to surge at moderate acceleration. Don't get me wrong, at wide open throttle the car hauls. I don't track the car, just light to light drags and having a blast. Get some comments from the more experienced but again, overall, I'm very pleased with the tune for my style of driving. Good luck and be safe.