I think you may have made a bad move mate, have heard that IRIS is crap, one was so bad it was flexing & hitting the tyre sidewall
.
If you have already fitted it check the play on it while it is on the rear sprocket & what side play it has.
A good quality chain will be in the £80 region, just remember the amount of power that is put through your chain, if it snaps it can destroy your cases
.
Sorry if this a bit of a negative reply.
Chris.
[Edited on 8-8-2003 by chris.p]