Carlos G posted:Jim does have the camera pretty far back on the car, so it's picking up a little more sound than it would if it was up near the driver.
Sounds fantastic to me.
@Carlos G is correct about video! I have the GoPro mounted in typical location on body just behind convertible top. I used duct tape to attach an MP-3 digital recorder on the bumper just above the exhaust tip. Did this for 2 reasons.
1. GoPro video to show shift points (exhaust note) relative to car's speed. GoPro built-in mic would not properly record exhaust note due to surrounding wind noise and distance from exhaust pipe.
2. MP-3 digital recorder duct-taped on bumper above exhaust for more accurate sound and volume of exhaust note.
I synched the MP-3 recording with the GoPro video for effect of exhaust note relative to shift points. In editing, I gave more bias to (enhanced) the MP-3 recorded sound over the GVoPro wind noise. Actual sound of A1-Sidewinder when driving is not as pronounced as in this video but more subdued while remaining pleasing to the (gearhead) ear. 
@wombat
FWIW - the Tri-Mil exhaust is a much more restrictive exhaust system than A1. Unequal length of exhaust pipe (from each respective exhaust port, to the resonator/muffler) is manifested in a fluttering wave pattern of exhaust velocity (causing a slightly restrictive backflow).
A1 is a system that has all exhaust pipe of equal length into a collector/extractor minimizing if not eliminating backflow which results in enhanced engine performance.
I could be wrong, but that is how I understand it. Hope this info is useful. 