I would run a 163, I am running a 156, haven't ridden with anyone who has 163, so I can't say from experience, but I do think that the 3" 156 needs an aftermarket skid for it to work at its full potential (coupling). I do like my track, but I just haven't felt the hype, in no way will run with a 6-7lbs of boost, I highly disagree with anyone claiming this.
I should have played with my suspension set up a little more to see if I could get different results, and I really would like to see how the 156 would work with coupling, think it would work much better.