i myself have a viper on mine, cheap and cheerful and sounds nice, but and its a big BUT its a complete tw*t to fit, the connecting pipes for the cans are a fraction too small to fit over the downpipes so either get one made up or if you dont mind a bit of bodging you can make it fit but isnt that tidy.
i cut a number of slots in the end of the connecting pipe that goes over the downpipes and then blow torched the end and then forced the pipe over the downpipes (with a lot of persuasion) once cool wrapped an exhaust bandage to seal the join.
not the most text book solution but one of the cheaper ways to put a new race can on...
