That picture is the factory 2-stroke pipe. The 4-stroke has a really big ugly silencer. I think fmf makes a pipe for it that probably would shave off 10 pounds of ugliness.
They are working out great. They are the exact same arms that ATK is putting on the MX now. A friend of mine ordered some from ATK around the same time I bought yours and they are identical. Except the ones I got from you were about 1/2 price. Thanks again for the great deal.