I'm always hearing about tuned exhausts here, and frankly I have my doubts. How can an exhaust system really improve the motors performance? Doesn't all the motor's own internal workings occur before the exhaust, and isn't that just to carry away the by-products for the next ignition sequence? Surely if anything impedes the exhaust flow to any degree, this will hinder performance- to that end I personally drilled some small extra holes in my endcap- because it was smaller coming out at the bottom than the exhaust manifold at the top. The idea of straight header pipes in loud hot rods is that then there isn't ANY muffler to impede flow in any way. But how can any exhaust system really IMPROVE how your motor runs? Don't get me wrong, I'm all for quieter running and I think the answer is a longer pipe and bigger chamber. I just don't think any real problems can be solved or improved worrying over exhaust, if it's not already restricted somehow.