I recently bought a used 2003 Predator and it has a Pure Polaris silencer on it and I have a question or two. It seems unusually loud. I am normally a two cycle guy and don't know much about this. Can you add or subtract disc's to change this and if so, where do you get them? Also, it is stamped closed circuit use only, or something like that. I m assuming that it does NOT have a spark arrestor. Can a guy get a disk with a screen on it or because it says , "closed circuit use only" that it would not be legal anyway. I hate to have to get another one. Not exactly cheap. Is there anyone with a owners manual they would be willing to part with for this unit? Thx....Dean