Crossflow exhaust

Ok, it's nearly ready for an exhaust. Will be taking it to the dyno for tuning the carbs but will need a exhaust beforehand. Looking for a sporty but not overly loud note - and as free flowing as is realistically possible.

FWIW, the engined has had a bit of work done to it: valves, ports, cam, extractors, etc.

So interested in what exhaust set-up others have found works well and sounds nice.

Thanks Ian