A true merge collector is fabricated from individual tubes that are cut, fit, and welded so the exhaust paths merge smoothly to a point. It is not just a formed cone with a piece dropped into the middle. That smooth transition is what separates a real performance collector from a generic part that only looks the part from the outside.

See how Burns Stainless Single-Stage race mufflers reduce exhaust noise while maintaining flow, low weight and performance for demanding racing applications.