Originally Posted by Socale92
i really want performance headers. they made a huge difference on my e46 m3, thx
As has been stated, the stock headers are very high tech hydroformed units. Swapping them out will not yield significant gains. Taking off the cats is irresponsible and don't most states require inspections.
"Innovative exhaust system
Through its design and configuration, the exhaust system for the new V8 power unit optimises the cylinder charge cycle, ensuring an optimum surge of power and torque at all times. And again, this component has been designed and built from the start for consistent lightweight qualities.
The exhaust manifolds are made in an internal high-pressure remoulding process, the desired contours of the stainless-steel pipes being shaped from inside under pressure of up to 800 bar. The result is extremely thin walls measuring just 0.65-1.00 millimetres (0.0256-0.0394") in thickness, optimising flow conditions with minimum resistance, light weight, and optimum response of the catalytic converters." S65 press release