It is commonly believed that performance efficiency can be improved by reducing the secondary exhaust pressure from the turbine. The torque will be affected when the pipes diameter is too wide.
We here at Tomei had invested over a year in researching all possible aspects and combinations for the best performance gain throughout the entire area. The end result was a decrease in exhaust resistance in all areas and best results is achieved with our Outlet ( dump pipe ) and front pipe as a combined set.