I just experimented making my own silencer. I took off my FMF Q exaust cause it needs repacking. I weighed it and was about 6 1/4 lbs. The stock titanium head pipe is 1/2 lb so that gives me a total weight of 6 3/4 lbs. I'm not sure what the stock WR exhaust weighs, anybody know? I think its like 8 pounds or more. Anyway, I took apart the Q exhaust, and pulled off the can. it was heavy. The mid pipe was 1 1/2 lbs. I used this as a start for my own muffler. I took some thin sheet aluminum from an old dish washer I had junked and used it to make the can. It is fairly thin and would take a couple spills on the bike. Hard crashes would ding it pretty good, though. Anyway, using the Q mid pipe, I wraped the sheet aluminum around the flange and drilled holes to match up with the midpipe holes. Then I took the spark arretser and slid it in the other end and wraped the aluminum around it. This gave me the oval shape. I took what was left of the original packing and wraped it around the tube with holes in it, inside the can. So basically it is a straight through exhaust. To seal the can, I overlaped it on the back side, ran a generous bead of hightemp rtv, and used sheet metal screws every 2" to close it up. The final weight was 3 lbs!!!! If I redo it with a titanium mid pipe, I think I could shave off another 3/4 pound for sure. So now my whole exhaust is 3 1/2 pounds, total. I was thinking that power-wise might not work too well ( I was just kinda fooling around building this just to experiment). So, I fire up the bike. Whoa! It sounds pretty deep. Has a real good sound to it. It's loud, but not nearly as loud as I thought it would be. It only has half of the packing in it, so it should be even quieter when I repack it. Oh the length of my new silencer is 14". So now for the ride. I take it up the street. It definately revs quicker than the Q. But the Q purposly slows the revs to help with off road traction. It has NOTICEABLY more over-all power than the Q. I was suprised. So I don't think I screwed up too bad. I'm really curious to put it on a dyno and compare the difference thoughout the powerband. I't would be cool if I could try several different designs and gage the gains and loses. Anyway, I'm gonna redo it a little nicer and loose another 3/4 lb off the mid pipe. For me its a keeper! (until I smash it crashing, and then I 'll build another) It cost $0 for me to make this scrounging up parts. I'm sure there is a lot more to making an exhaust that I am missing, but I'm going to dyno it and if it performs well, I might make a few of them and sell cheap to freinds. Less than $100.