If on one bank you are going to merge it to one in order to put a turbo on, then take the one large pipe out of the turbo and somehow merge it to the four small collectors from the other bank in some form of a 180 setup, the answer to your question would be: Absolutely no effect on the sound, assuming that the sound of the real thing that you are trying to duplicate is a Harley Davidson. This setup is going to be a poor performance option as ShulzeA said, is going to be difficult and expensive to build, and is going to look worse than it sounds or performs. Why do you want a turbo in the first place? A decent LS will make more power than you can ever get to the ground.