No problems here... this thread makes me cringe coming from an 8th gen Si. Pleaseeee don't let the 86 have this problem too!
Only gear I've partially grinded was second and I know that was my fault on the clutchwork.
I have noticed that downshifting to fourth from sixth can be a bit tricky and I often go back into sixth. It's kind of funny at times, trying to rev match fourth to overtake only to get into sixth again.. very anticlimactic.
Replacing the shift knob earlier today has made this easier for me to avoid!