i am planning on getting exhaust for my 300 it is the twin turboed model and I am wondering if I need back pressure and if I do how could I achieve that back pressure whilst still getting flow through I am planning on getting 3 inch turbo back exhause with no cats and mufflers at the end will that be god for back pressure if needed

 

That back pressure **** is nonsense. Exhaust is just s piece of pipe that directs the gasses to the back of the car and also cuts down on sound by resonators. You could honestly make your own exhaust at the muffler shop and it wont cause that much drama. If you still want to get an aftermarket, hks has good ones. Search it

 

Wanting back pressure is BS, but you do need it to flow well. Too small and you restrict the gas flow, too big and you have turbulence which also restricts flow. The shape of the system plays a big part too, every kink and turn hurts the efficiency of it.