I have a C7 3.0T sline and I want like many of you have some sound coming out of the back and I saw alot of thread about the x pipe (middle resonator deleted), but when I ask the shop he told me he does straight pipe all the time for s4 and s5, so he told me he doesn't see the point in putting a x pipe. What do you think, is there really a difference between the two and if there is what would be the best choice for this car?