yes i have, i understand and i will say the results are you lose torque and gas milage, when i tuned the car i made up for more than the torque and mpg lost. also the way s4 aux ports work is back pressure. my car had a straight pipe = no back pressure so the ports didnt open. therefore i had to wire them open. thanks for the question tho i hope that answers your question. its common practice for fc owners w/ exhausts. thanks

i dont really wanna selll for cash but if i did 3500 i guess