best big bore/clubman for mixed riding

I have a 150Li S3 and Jetex 22mm carb with standard 32mm exhaust .
I need to replace the exhaust and downpipe and wondered which clubman type exhaust would give the best performance gains for twisty country B roads and occasional short carriageway runs ?
Probably not looking to use more than 5000-5500 rpm tops on this old engine so need gains between 2500-5000rpm rather than 4000-8000rpm
I need to replace the exhaust and downpipe and wondered which clubman type exhaust would give the best performance gains for twisty country B roads and occasional short carriageway runs ?
Probably not looking to use more than 5000-5500 rpm tops on this old engine so need gains between 2500-5000rpm rather than 4000-8000rpm
