Your upgraded Yaris Nitrous Kits will make others green with envy. To get the most bang for your buck, invest in a Nitrous Kit. We have many Yaris Nitrous Kits. A Nitrous Kit can double your horsepower depending on the size of your engine. Yaris Nitrous Kits are a great upgrade. Make your vehicle much faster with a new Nitrous Kit. Nitrous Kits are the easiest way to add power to your vehicle.