The Rush was discontinued about 3 or 4 months before the Firestorm came out. If you do a search you will see there are a couple of old threads on it. As far as a pipe has a lot to do with what you are looking for and how much you are welling to spend. Make sure you buy a lot of extra parts particularly the weak middle gear in the transmission. Make sure you have the slipper clutch set properly at all times.
Good Luck and have fun.