Hey I also have a 98 Prelude with the Jackson Supercharger!. I personally think the gas for supercharged cars is not quite worst. For the most part, I think you can gain mileage depending on how you drive. Well that was for my prelude, the jackson charger actually bypasses the charger and recycles the air while you are cruising, but once you step on it, the supercharger kicks in like a monster. i will get the trd for the scion too because i just like how chargers sound. nice whistling sound to it!!! hopefully gas is ok because the power sure will be worth the gas!!!