Performance Slip On Merge Collectors: 1 5 8" 5 into 1 2 1 Stainless Steel Merge Collectors 1.5" In Inlet Slipover Id 1.75" In Performance Slip On Merge Collectors: 1 1 2" 2 into 1 Vibrant 4 1 SS Merge Collectors (2 1 4in Inlet Slipover ID 4in Merge. 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.