Oo. I have had a dull roaring noise when I accelarate rather hard. I just put a Bank's 4" exhaust on and now I have this noise at almost any speed particularly at the 70 mph and up range. I drive a lot of expressway driving and it is very annoying. I believe that it is from my turbo. Would this be a correct guess? Also if it is, is it liable to be a problem? Anybody who can help me. Thanks.