I'm I think up to level 19 and almost through all the licenses.How far are you into the game
Haven't started it yet.Bspec level?
I am more or less in the same position as you, having recently started playing GT5 again where I left of in 2011.
See https://www.gtplanet.net/forum/threads/version-update.315108/
I have skipped the Japanese Classics initially because I couldn't find a suitable car back then.
I won a Toyota 7 Race Car '70 in B-spec "Like the wind" level 21 which I used to come back to win gold trophies in the Japanese classics in both A-spec and B-spec.