both, the responsiveness and idle are smooth, the mileage even with superchips 90 tune is much better when I'm not driving a maniac.
my best mileage hand calculated was on regular trip to Utah, always the same route - just over 19 mpg @ 65 cruise control all the way - even when posted was 75, weather was perfect no additional headwind!
my setup 2010 auto, superchips 90 tune, 35's. 4.88's, screamin demon w/ livewires, dynomax vt and cruise control! usually on the freeways I average 15-18 depends on foot and headwind, around town about 13-17 depends on how lucky i get with the green lights :thumb:
I should mention I got the demon coil setup when I installed my lift and tires - this was before superchips, gears and muffler - it made a difference and with each mod more improvement to get what power the 3.8 has out of it.
