[bigred90gt]

2 1/4". I wouldnt say that they are really restrictive, but you can get somewhat of a better flow going with an aftermarket catback. Alot of it has to do with the mandrel bends in the aftermarket systems as opposed to the style of bends (almost collapsing on the I.D. of the bend) that comes with the stock tubing. The size just opens the flow up that much more. Also, if you are running any type of forced induction, the need for a larger, better flowing exhaust becomes more apparent.


The "crimps" come from the pipe bending machine. It is like a pressed bend. I cant remember the name of the type of machine. But it is not from a vise.