Thanks again to Ed for sending me a silencer to work with. I studied different designs from different companies to try to come up with a decent prototype. I used mostly ideas from Flowmaster, but not copied exactly. Corsa actually has the best designs for the size, but there is way too much cost in time and materials to try and reproduce one for my KX. Here's where I'm at so far on the first design. I picked up some 22 ga. sheet and had some leftover 1/2" electrical conduit for some "chamber ports" I guess you would call them. I'm trying to keep at least the same amount of volume throughout the design to reduce a bottleneck/back pressure situation. The 1" strips will be the frame of the insides of the muffler. The plan is not to alter the aluminum housing, exhaust tip and front pipe.