I would like some info from those of you very familiar with Honda 4 stroke engines of 1985.

I have a Honda ATC 200X with a 200cc engine and I would like to know the difference
between this motor and the Honda XR 200 motor of the same year?

My 200X trike uses a NGK DR8-ES-L spark plug and the
XR 200 uses a DPR9Z spark plug.
What is the difference between the two spark plugs?

The whole reason for my interest is that years ago I had a friend tell me that a NGK
spark plug with a 9 in the part number would perform better in the ATC 200 engine
that normally used the DR8-ES-L spark plug.

Thanks
atC Rider

p.s. Yes I could just buy a DPR9Z and try it in my ATC. I want some other opinions though.