The Mercedes-Benz SL55 AMG has a different sized gas tank based on year and model trim.
Larger sized gas tanks are advantageous because you don't need to go to the gas station as often. Also, you can take advantage of days when gas prices are discounted and fill up your vehicle with a larger quantity of gas.
Scroll down for the gas tank size tables for your year and trim.
CarDataSpecs.com is a website designed to quickly help you find pertinent information about your vehicle.
Also, you can consult the vehicle's owner's manual.