MEET THE CREW
EFREN MERCADO
CHIEF EXECUTIVE OFFICER
Efren brings 29 years of experience in technology, business strategy, and customer innovation to GT International. Prior to co-founding GT, he led global go-to-market strategy for IoT at Amazon Web Services and managed a multi-million dollar portfolio of Fortune 100 clients as a senior consultant at Microsoft. At GT, Efren applies his deep background in digital transformation and customer engagement to drive growth, elevate the service experience, and expand GT’s reputation as the premier destination for European automotive performance, repair, and care.
WEBSTER MERCADO
OWNER & MASTER TECHNICIAN
Webster Mercado is the heart and soul behind GT International, a standout automotive service company in Austin. A factory-trained Master Porsche Technician and brand ambassador, he’s been immersed in the world of high-end cars for over 20 years. With a genuine love for the craft, he’s built a reputation as a go-to expert in luxury automotive care. He launched GT International, the first and only membership-based service for premium vehicles in Austin, to help his clients make the most of their most precious resource: time. Webster understands that a car isn’t just transportation—it’s a passion worth preserving. His deep Porsche expertise and thoughtful approach set him apart in the industry. He’s all about blending top-notch skill with a personal touch to keep his customers’ vehicles running flawlessly. For Webster, it’s not just a job; it’s about chasing excellence in every detail, executing top-tier service, and building a tight-knit community of car lovers who leave his shop feeling pumped and ready to hit the road.
Clayton Raley
SERVICE MANAGER
Clayton graduated at the top of his class at Universal Technical Institute in Houston, TX, and during his time at UTI, he was selected to attend the BMW Master Technician Program in Orlando, FL. Following graduation, he worked for BMW of Austin where he further honed his skills for 9 years. Before receiving his degree as a Master BMW Technician, he served 4 years active duty in the U.S. Coast Guard and is currently in his 15th year in the Reserve. The U.S. Coast Guard’s motto is “Semper Paratus”, always ready, so in addition to his skills as a Master Technician, this credo makes him an even more welcomed addition to the GT International family.
Jeremiah Jordan
SALES & MARKETING DIRECTOR
Drawing from his background in real estate, Jeremiah Jordan brings a strong expertise in sales and marketing to GT International. His focus is on enhancing the brand’s presence by highlighting the exceptional service GT International provides to its members. Additionally, he works to build strategic alliances with forward-thinking businesses that share the vision of transforming the automotive industry. Outside of work, Jeremiah enjoys hitting the golf course or firing up the grill, spending quality time with friends and family while catching a game.
Frank Sigler
SERVICE WRITER
​With a quarter-century of experience in the automotive industry, Frank has collaborated with leading manufacturers such as Hyundai, Kia, Subaru, Nissan, Toyota, Mitsubishi, Porsche, and Tesla. His passion for cars and problem-solving has driven him to tackle diverse challenges, enhancing his expertise across various automotive technologies. Outside of work, he enjoys working on his own cars, spending time in the outdoors and sharing these experiences with his children.
Mark Senoren
SHOP FOREMAN &
MASTER TECHNICIAN
Mark Senoren, the Shop Foreman at GT International, is a dedicated motorsport enthusiast and lifelong tinkerer with an impressive 40-year career in the automotive industry. Specializing in Audi and VW for the past 25 years, he has witnessed and adapted to the rapid technological advancements in vehicle applications. Known for his meticulous craftsmanship and unwavering diligence, Mark is not only an exceptional mechanic but also the shop’s resident comedian, keeping the team motivated with his humor and upbeat personality. His passion for cars and racing, combined with his deep expertise, makes him an invaluable leader in the shop.
Sean Magill
TECHNICIAN
Sean Magill has grown from an eager apprentice to a skilled technician at GT International, spending the past five years honing his craft and deepening his knowledge of automotive technology. Always striving for improvement, he continually refines his processes to become a more precise and efficient technician. Outside of work, Sean shares his passion for cars through sim racing with Mark and Dominic and enjoys tinkering with his own vehicles. His enthusiasm and positivity make him a valued team member, bringing great energy to the shop every day.
Dominic Senoren
TECHNICIAN
Dominic Senoren brings a strong mechanical background to GT International, having served as an Army mechanic for eight years before transitioning into the civilian automotive world. Specializing in Audi and Volkswagen early in his career, he later advanced to working on Porsches, further refining his expertise. For the past few years, he has had the unique opportunity to work side by side with his father, Mark, sharing both knowledge and a passion for precision engineering. Dedicated and skilled, Dominic approaches his work with discipline and enthusiasm—plus, he’s always up for a good taco.
Jaime Zartuche Jr.
APPRENTICE
Jaime Zartuche Jr. joined GT International as an apprentice after gaining experience at CarMax, driven by a lifelong passion for working on cars. Inspired by his uncle and the early 2000s car scene, he has been fascinated with automotive work from a young age. Known for his attentiveness and strong work ethic, Jaime is focused on advancing to a technician role and expanding his knowledge of Porsches. Outside the shop, he pursues his other passion—boxing—as he works toward his goal of going professional.
Bryan Gomez
APPRENTICE
Bryan Gomez joined GT International after gaining experience working with Cadillac. Passionate about cars, he has a strong interest in drifting and high-performance driving. Eager to grow in his career, he hopes to advance quickly into a technician role. Outside of work, Bryan enjoys spending time at church, staying active at the gym, and participating in outdoor activities.