More and more I hear that I should have a stock backfire screen in my '91 xr600r, but I don't have one, i've nevers even seen one (my bike came with out one). I have a twin air cage and filter in there now, should I run a backfire screen? I really would like to at least find one to try out. Does anyone have one of these laying around, or know where to get one? Can one be made, what kind of material is made of? Would I still be able to use my twin air setup with the stock backfire screen? Once again your experience and advice is greatly appreciated.