I'm assuming you mean Aurora? I was comparing a T8 head+gloves setup to 4pc T9 + Aurora a while ago and Aurora+4pc came up a bit less than 1% better in terms of raw dps. I don't have the simcraft dump on hand right now though, but I'd imagine you're looking at an increase of about the same magnitude (or smaller) going from T8 head+shoulder.
Yeah, i ment Aurora. So if its that small of an upgrade, ill just stick with my setup and wait for 9.5.