Maybe he installed it in the Spring and got improvement as warmer weather thinned oil and air, softened grease and rubber, and increased tire pressure.I actually read another thread on here somewhere. Somebody installed the Mopar CIA like they put on the GTs, and said he picked up 1 1/2 mpg. It had a low restriction filter, and like one commenter on that thread said " they don't put it on the GTs for nothing.