Personally, having never watched the 83 version of LOCH, I can't really say much about how the story differs.
I've only watched the 2003 and 2008 version. And I love the 2008 version so much... it's crazy.
My grandma says the 83 version was the best though, and well, my grandma is like an asian entertainment expert. She actually introduced me to Jay Chou, and she's like, seventy-something? lmao.
Hu Ge is an amazing Guojing! And Ariel Lin played Huangrong really well! They are the cutest couple ever!