2" Inlet 2 3 4" Outlet 4 Into 1 Weld On Merge Collector 304 Stainless Vibrant 2 1 SS Merge Collectors (3in Inlet Slipover ID 3 1 2in Outlet Vibrant 4 1 Stainless Merge Collectors Vibrant 4 1 Stainless Merge Collectors Performance Slip On Merge Collectors: 2" 4 into 1 Merge Collectors Radiant Speed Works. Vibrant Performance has developed a comprehensive, high quality and Affordably priced range of 304 Stainless Steel Merge Collectors to help our customers free up maximum horsepower from their exhaust setup. For many years, merge collectors were almost exclusively used by top professional race teams. However, this proven technology is now commonly used at all levels of professional racing (where rules permit) and now many fabricators are incorporating merge collectors into street header applications.