RE: Arrow wobble
I shoot an X3 and like it.
Anyway, there's no way to give you a definitive answer. I don't know anything about your arrow spine, but it could be part of the problem. Is there an on-line arrow selection chart by the manufacturer of those arrows? Your archery shop can check it for you too.
You say a couple arrows, maybe it is just those specific arrows? If not, it could be that you torque the grip every now and then.
After checking those issues, I would look to tuning. Always a good idea to get it tuned as well as it can be, even if you think they're flying OK.