So in this case are the IN-8s better choice than the IN-5s because of flatter off-axis response? 10k dip almost disappears on the off-axis curves, while the IN-5s are only getting worse in this range. Can´t decide between those two, but what are you saying makes more sense to get the IN-8 monitors. On the other side Erin reported about noticeable resonance in the lows, which the IN-5 monitors don´t have.
Even so, I probably would pick the IN-8 v2 if size of the box were not a very important factor to consider. Maybe if my use case were only for a surround satellite monitor, I'd be happy to consider the IN-5. Well, even the much larger sized (and more expensive) Sceptre S8 has some box resonance -- which I was able to reduce some with additional damping and mass reinforcement -- though, I'm not so sure if the latter had much of an effect.