do a search mate. There's loads of threads on whether chatter is harmful on the turbo or not.

MFI chatter: I've got it on the S1, but not on the S2. Both running same boost. They say if the MFI chatters, then the air sensor plate spring is weak: hence why it chatters. I think that the plate doesn't shut quick enough to stop the air escaping, but only stays open for a short time & this is why you get a bit of chatter, but not as much as with the EFI cars.