I'm thinking about buying one for my Astra.
There's a perforated butterfly valve in there which is supposed to increase 'back pressure' (actually it increases the scavenging effect).
You can open/close the valve as much as you like to tune for sound or performance, or have it (some how?) linked to the throttle. I think it would make more sense to have it linked to the number of revs that the engine is doing. what..
Thing is, does anybody have any experience with it, or it is all just marketing faff?
http://www.lmfvauxhall.co.uk/Remus-main ... ystem.html
Not z22se related, but an interesting read:
http://forum.e46fanatics.com/showthread.php?t=539894