Hi! Look at photos. Who did that? It does not harm the engine? Ventilation gases, and the like.
(http://ipic.su/img/img7/fs/muffmod02.1443279025.jpg)
(http://ipic.su/img/img7/fs/muffmod04.1443279081.jpg)
(http://ipic.su/img/img7/fs/muffmod06.1443279099.jpg)
(http://ipic.su/img/img7/fs/pipes1.1443279119.jpg)