Exhaust thing turned out perfectly. The carb info on this site (thanks Creeper, Meat and everyone else concerned) is amazing. I punched a few 10mm holes in the back plate of the muffler, re-jetted carb to 152,5, raised the needle, reduced rear sprocket by 2 teeth, and now she is pulling like an ox, it's amazing. Or like a camel I should say. Better than having a new bike. I took it to a friend who tunes bikes for desert riding, he insisted on pulling off the part indicated in the pic (is that the snorkel?). Seems to be a heck of a lot more air going through, might be my imaginantion but I think i can actually hear the airbox sucking. But it's feels extremely good, not lean at all, smmoth acceleration all the way through. Anyway I could go on and on but suffice it to say I'm very happy.