I am interested in installing an aftermarket muffler/spark arrestor on my 04 WR450 for an 'across the board' power increase and hopefully some reduction in noise. Where I ride, noise is not a factor, but I would rather set a good example if possible. Performance is the priority, an not just a big hit down low or up high in the powerband, but all over. If I can reduce the noise output to less than the stock unit (without the insert) that would make me happy also. Oh, the bike is stock with the exception of the 'free mods' and a JD Jetting kit installed. Thanks in advance!