ThanksFirst of all, congrats on your purchase!
-91 octane is required by Honda, not recommended
-I personally experience the 3rd gear grind occasionally and it does pop out sometimes... I think it's how you shift as well as the actual gear having a little problem (I haven't had an oil change yet, so dunno about the whole Amsoil thing)
-even if it doesn't grind, the 3rd gear is hard to go in smoothly, you're just going to have to practice and get used to shifting into that gear specifically
Lastly, enjoy =D