I have a '98 as well- bought new. I have never gotten good has mileage but don't really care. It's a motorcycle and I ride it fast. I also weigh around 230 lbs. Last summer I did a mileage comparison between using the Power Commander and without (running non-ethanol 92 octane gas). The difference was small. The PC gave me a bit better gas mileage and certainly better fueling. The actual numbers are posted on this site. My only mods are the PC, K&N air filter, and a Vance & Hines titanium pipe. Ride and enjoy! Sent from my SM-G955U using Tapatalk