Hi folks newbie here and i have a few probs with my 407 1.6HDI.Its a 2005 with 79.000,the problem is i am getting a wierd noise coming from the engine bay what can only be discribed as a whoo whoo whoo.I have not long had some work done on the car i.e new center section of the exhaust and new air box and all pipe work too and from the air box.The car sounds like its got a K+N fitted although i am 100% sure it hasn't.Very noisy also at high revs i get a rattle.Any ideas folks thanks in advance.