A complete dyno tune with wide-band O2 is probably the best way to go.
As for changing programs, I have a "dip switch" that I routed into the glove box where I can change b/t programs. As stated above, my chip came with program parameters that are activated by the different positions of the switches.
I am very curious as to what type of gains I will see in the 1/4. Throttle response does seem to be better - but again this can be difficult to tell. I will definately post back about the results of my alum. fly and JMS chip combo. I want 107 mph and 12.9 out of my stang on drag radials, that would make me happy!
E
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1991 5.0 LX Coupe - 38,000 miles
13.17 @ 106.14 mph w/ 2.138 60'