I wouldn't care to say. I'd expect the result to be very close. With respect to the passion, though -- you probably can't get more passionate about voting than the "Yes Scotland" Camp, but in the end the signs that they were going to win or come scarily close was enough to compel all the quieter "no" voters to turn up. A similar thing is possible here. If things look like they are going to be close then both sides would be, I hope, encouraged to turn up -- in particular, that might negate the passion of the Brexit supporters.
I'm worried, either way, that the result is going to be so close that it's hardly decisive even if we voted to stay. Nothing short of a total hammering for Brexit would convince them to shut up about it, and that's hardly likely. I don't see it going more than 55-45 either way, and at this stage that's basically a dead heat.