Help identifying this waste gate!

[paradoxx]

Hi there,

Can anyone please tell me whats missing? and what this "wastegate" is?
I got it in a box. off a mate who got it in a box, and i realy have no idea what it is

The only thing i have left in the box thats not in the pictures is the screamer pipe, but apart from that, thats all ive got!!

Any info would be great!!

http://home.pacific.net.au/~dboman/wastegate/

Thanks

Ian