I have a manual transmission with a tuner. I like to run the 87 performance program because it still has improved performance over stock and also has some improvement in gas mileage. If I want more power I switch to the 91 torque program. Performance is definitely enhanced but I don't get enough improvement in performance to justify the higher cost of premium gas.
I was not that impressed with the 91 performance program. It did give me the best gas mileage of all the programs but did not give me the best performance at the rpms I like to run. I think the 91 performance program is good if you like to run to red-line or over but with my typical driving, it does not suit me. I am not out there drag racing at high revs all the time.
2002 FX4 Bright Red Supercab 4.0 SOHC, manual 5-spd & Tcase, 33" BFG MTs, K&N air filter, Modified air box inlet, Gibson SS cat. back exhaust, Bama flash, Hidden Hitch round receiver, Rear helper air springs, Electric trailer brake controller, Line-X bed liner, WAAG bar with KC lights and Wildernest shell.