Unequal length runners on the headers achieve the unique boxer engine rumble.
The OEM headers restrict air flow resulting in loss of power and efficiency.
Tomei headers do not restrict air flow resulting in an increase in power and efficiency.
The OEM headers greatly restrictair flow right after the engine port.
Unlike the OEM headers, Tomei headers do not restrict air flow right after the engine port.
The turbo side of the OEM headers severely restricts the flow of the exhaust gas, resulting in loss of power and efficiency.
The collector on the Tomei headers were made using the lost wax method. The lost wax method allows the collector pipes to merge smoothly, therefore eliminating any restrictions on the header.
The OEM headers have multiple restriction points which results in poor exhaust flow.
Tomei headers have an even 45mm piping from the engine all the way to the turbo, therefore allowing the exhaust gas to flow smoothly.
The OEM headers turboside port is severely restricted by its 33mm port on the header.
The slide adjuster on the Tomei header allows users running thicker headgaskets to appropriately extend the header to accomadate for the thicker headgasket.
The flange on the Tomei headers is highly rigid, lightweight, and has a stepless flange.