I'll assume thats the smaller US gallon as in imperial gallons its 2 and a mouthfull to fill the teeny tank. I get about 75 to 85 miles out of the tank (the drier the weather the less the mileage) on my daily commute with BC Tips (cat still in place), dropped about 10 to 15 to the tank compared to standard pipes (or maybe I just thrash it more now).
0-60 in .......oh! wait.... I really don't care anymore (but it's still 1200cc of raw throbbing Trumpet so bugger off Mr.Scooter!)