I answered elsewhere. fyi the pipe is an upgrade and apparently the carburetor too. I sold the stock exhaust off of my 95 and the carburetor when I modified. I think the man said on another form it felt like about a half a gear better. now whatever that means. when he did it, he took the stock snorkel off the air box as well I believe. then the xr250r carburetor was jetting for that as well. fyi my modified bike uses a pipe more like some of the accessory manufacturing companies were making for it. it came off of a 79 xr500 which has the same port to port dimenisions as the rv head on the xr250 you have. i cut the header pipes 1.4 inches and used the stock collector which was bigger than even the xr250r pipe was. with a 32 mm carburetor and a much wilder cam and a 280 kit the difference was noticeable using the same supetrap silencer I had with the stock header. not really enough to make it worth doing, and the rest wasnt really worth doing either. I took a great slick surface trail bike and made it quite a bit faster on sand. and a little bit harder to ride on slick stuff. it still wasnt as fast as my yz125 in most places where acceleration was concerned, but gained in top end.