Well I am sure there will be some nay sayers out there but here it goes. My wife bought a 2000 kia spectra, brand new, and we immediately took a road trip. On our first 800 mile trip we averaged 32 mpg. 2 weeks later I went to buy a K&N air filter and the guy showed me a tornado. I was skeptical, but explained that if I wasn't satisfied he would give my money back plus $10 for my trouble. I bit. I installed the filter and tornado in the parking lot. I noticed a minimal increase in performance, but an increase none the less. The kicker came 2 weeks later when we made another 800 mile trip. 36 mpg. I was hooked. I also bought one for the bronc (carbureted). A big waste of $70. I guess that the efi 4 cyl was more responsive to the increased air than the carb. I never tried adjusting the carb, didn't see the point. With the X's efi it may make an improvement, I don't know, never tried it. I have had other friends experience same results on their fuel injected vehicles. If I am not mistaken the tornado is "satisfaction guaranteed". They had no problem taking back the one I bought for the bronc. Try it and if you don't like it all you wasted was the few minutes it took to install it.