It looks excellent. I haven’t seen the original. Recommended before the series debuts?
I'm going to watch the original afterwards, but I've seen it many times over the years. It won awards at the time and set ratings records, but it's not a fast paced thing. Also, there's a lot of Japanese dialogue without subtitles (it was done on purpose, as the central pair are the foreigner and his interpreter), and it's from 1980, so I'm guessing that you'd be better off either watching it in installments or watching it after the new one, so you can just stop if you find it's not your thing.
But that's just me guessing about how you'd feel, and I may well be wrong on that.