T Sportline is a Los Angeles company that prides itself in being the world's first Tesla tuner. Owner Elie Rothstein and his team offer Tesla owners the chance to add all kinds of aftermarket parts and accessories to their cars. One of the company's most coveted offerings is its super exclusive T Largo Edition Model X. Limited to just 20 units with each worth as much as $300,000, these SUVs are fully customized inside and out. We stopped by T Sportline and followed Rothstein through the entire process of tuning a Tesla.