What exhaust??

[solorider]

I looked on the Arrow website and could only find a full system for a Gen II.  If they still do a Gen 1 system, that's good because they're a decent make.  Looks like they favour a 4-2-1 set-up, like Akrapovic do for the Fazer.

The Arata system is a 4-1, hopefully with a horizontal merge plate in the collector.
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generally a 4-1 will give an increase in the top end and losing out at the lower and midrange where a 4-2-1 will give better results in the low end and midrange with a smaller increase at the top end, I know when I had a blackbird which has a 4-2-1-2 as standard and I fitted a 4-1-2 the power delivery was changed, the bottom end was the main difference and at 6k revs the bike revved harder than before.