c4 with cast alloy back boxes?

[steveo3002]

seen a c4 advertised with rar cast alloy back boxes, never heard of these before and google hasnt any info

is there such a thing ? just intrested

[LuS1fer]

I've never heard of them and doubt he knows what he's talking about. You see some cast alloy inserts for mufflers on dirt-bikes but I can't see any advantage to such an item.