One thing to keep in mind is that mpg will be effected by the elevation you live at, this is commonly forgotten. My Axiom has an onboard info center that tells me i get 17.5 avg mpg with a very heavy foot and my 22s. I did notice a solid 1.5-2 avg mpg increase with my intake kit, and another .5-1mpg with my exhaust. Even with the way i drive which is very agressivly i still get decent milage. Remember that my Axiom is quite a bit heavier than the VX but has the ecact same drive train. The biggest factors to good mpg are clean air filter, regular oil changes with quality stuff, and good gas. I have found the last one to be a big factor in my area, if you get the cheapest gas you can find from the "U pump it"you will get a noticable amount less mpg than with a quality gas such as Shell or Texaco.