helped a friend put a throttle body spacer on his '01 4.0 wrangler...i couldn't tell a crap's worth of difference, now maybe thats just me, and maybe you can tell a 1 or 2 mpg increase if you keep up with your gas mileage but i dunno...i would stick with the air intake, i had the K&N FIPK on my '94 5.2L zj and now on my truck, you can tell a big difference in responsiveness on both applications, and it will give you maybe 3-6 more mpg depending on how you drive
sidenote: i have noticed that after performance modifications(exhaust, intake) my gas mileage tends to stay about the same...i think the louder the vehicle is the harder i push the gas pedal
