With all the noise restrictions on the racetracks i am wondering if anybody has used a active noise cancelling system on his racecar yet?in my racecar i have a porsche 956 bi turbo engine where the turbo exhaust exits in front of the rearwheel and the distance of the exhaustpipe is only about 30cm! If ANC would work it would not change the backpressure on the engine because of mufflers it also would solve the space problem. Thanks in advance for any advise. Petr