RENNtech, founded by Hartmut Feyhl in 1989, has become the premier Mercedes-Benz specialist in the United States, widely recognized as the top authority on Mercedes tuning. Feyhl spent 12 years at AMG Germany before serving as the Technical Director of the North American division after the tuning company's merger with Mercedes-Benz. At the request of AMG Germany, Feyhl started RENNtech to service the existing AMG North America customers, branching out on his own.

Since then, RENNtech has expanded its services to include tuning solutions for Porsche, Audi, Bentley, and other European luxury vehicles, in addition to becoming the foremost authority on customizing and tuning AMGs and Mercedes-Benz cars. They also offer a range of high-quality aerodynamic parts for Mercedes-Benz and AMG vehicles, designed and engineered to improve the vehicle's aerodynamics, enhance its performance, and give it a more aggressive and stylish appearance.

Over the years, RENNtech has developed high-performance products for virtually all Mercedes-Benz AMG vehicles. Some of their most notable achievements include the RENNtech E7.4RS, which achieved "Fastest Sedan in the World" honors from Car and Driver Magazine in 1996 with a top speed of 200 mph, and the recent RENNtech R3+ Monster, which boasts an impressive 945 LB-FT 5.5L V8 Biturbo engine. These vehicles showcase RENNtech's commitment to extreme performance, upgraded aesthetics, and a fit and finish that rivals factory vehicles.

At RENNtech's facility, they design, engineer, and manufacture their proprietary line of tuning products and aero parts in-house. Their facility includes a full fabrication and machine shop with CNC and rapid prototyping capabilities, in-house performance dynos, complete engine management and software tuning capabilities, as well as a complete service/repair/installation facility staffed by a full-time design, engineering, and sales team. With a foundation of performance without compromise, RENNtech has built a reputation as the premier tuning and customization company for luxury vehicles.