Same here, I am currently data logging for my TT build and I only have 91. I mixed 100 and the tuner said the fuel was good with a mix of the 91 and 100 but there is still false knock at about 7k rpms and at that shift. I am going to install a meth kit next week but not sure what else it can be...
i got a set of kooks green catted headers 1 7/8. link below
KOOKS LT HEADERS W/GREEN CATS - 2015+ S550 Mustang Forum (GT, GT350, GT500, Mach 1, Ecoboost) - Mustang6G.com
looking for a procharger stage II complete kit in black. new or slightly used is ok. email me at [email protected] or text at 805 637 8064 if you got any info on one. if you have something similar let me know.