Hi
Where in the UK do you live?. If you are in the south east take a look at
http://www.solentsupermotos.co.uk
This group organises run outs etc all through the year and has members in Portmouth,Southampton, Reading, Basingstoke, Borden and all points in between.
The run outs arenormally road biased, but with a few gentle green lanes thrown in for good measure. The group has quite a few members with MZ's so you wont be alone.
This site is still better for tech tips and help though.
If you are looking for a lighter, road legal exhust try the BSM pipes. They do not give much or any more power, but look a hell of a lot better.
Keith