Since IÂ´ve read so much about the advantages in sound and power when youÂ´ve drilled the silencers I finally decided to do it. I made a 2Â´2 cm diameter hole in every muffler but I am not happy with the result. The one on the right sounds well, but the one on the left, where only one cylinder expels gas sounds awfully rattling a lot when I throttle. IÂ´m afraid IÂ´ve spoiled the exhaust and I think will have problems with the MOT. Has it happened to any of you? IÂ´m surprised because they sound pretty different and I donÂ´t know what IÂ´ve done wrong. Thanks.