[Neonsxt0486]

I have a 2004 Dodge Neon Sxt 5-Speed with a Cold Air Intake and Catback with just a resonator no muffler. I'm filling up with about $18 and gettin about 190 -200 miles per tank? I know my brothers got a 1st gen that gets about 300. Is this a problem or am i bein picky. Thanx , Brian