I have a 2003 WR450 that I want to install a stock 2007 Wr450 header pipe and silencer on. I know that I will have to modify the mounts. Have any of you done this before? I can use some advice on the best way to modify the mounts (or any other advice you want to give me). If I just use the 2007 header pipe will it bolt up on the 2003 and work with the stock 2003 silencer? I have read some posts that say the 2007 header pipe may be too large to fit the stock 2003 silencer but I wasn't 100% sure if they were referring to the WR or YZ header pipes. The reason I am doing this is because my titanium header pipe is crushed on my 2003 WR450 (it was that way when I bought it). I have access to a 2007 WR450 header pipe and stock silencer (if needed). If I can make it work I would like to use the 2007 silencer since my 2003 silencer doesn't have the insert to make it quieter. I don't post on forums much but I really enjoy reading the posts on Thumpertalk. This is a great site! Thank you for any replies!