So I ordered a 4" turboback for my E99 f250 6 speed. The down pipe was 1/16 inch away from the bellhousing and the exhaust rattles like hell. Nothing in the fitment notes said there would be a problem. I talked with the vendor and DE before I ordered this system. Told them it was an E99 6 speed and both said it would fit fine. After 2 months af back and forth they tell me that they are sending me a new downpipe. They said the vendor should have know that it took a special kit. The guy at diamond eye said they were shipping it out last Thursday. A week goes by and nothing so I call them. I get some lady and she is about rude telling me that they dont do that and there exhaust should fit. Maybe I did something wrong. She takes my number an says she will call me back. I get a call back and nobody has shipped anything. The tells me that the 4" downpipe wont fit the 6 speed. She then tells me they are going to ship me a 3.5 inch down pipe. I am like WTH thats not a 4" system. I am told sorry thats just how it is. She takes my name and address down and says she is going to send my a 3.5 inch downpipe. So I guess thats what I am stuck with. Just an FYI for you 6 speed guys with an E99.