I didnt saw much topics for fiesta st here, I hope there is few owners...

I need information about flexy pipe. On fiesta st standard flexy pipe is the thightest pipe in exhaust system, it have only 42 mm (same as KA 1.3) , so there is restricted air flow.

does someone change it for miltek or moongose flexy pipe (60 mm) and is there any feelable increase in torque (someone told that there will about 20 Nm up, and about 5 bhp) ?