Oval tubing gets you past the crossmember, but the muffler and the tips are round. This transition makes that change in a smooth 6 in. section instead of a crushed pipe end, so the flow area stays consistent through the swap.

Vibrant Performance 13170 Oval to Round Transition Adapter Features:

• 3 in. nominal oval on the inlet end.
• 3 in. outside diameter round on the outlet end.
• 6 in. overall length gives a gradual transition.
• Formed from 304 stainless steel.
• Weld-in design for custom exhaust routing.