I am no expert on the 8 but do have one and love it. So will you.
As far as I know, it is a clean design coming after the RV-4. There have been no major changes except matched drilled holes with CNC machine.
They major difference from one airplane to another are engine and propeller.
The IO360 (200HP) with CS prop seems to be most common. There are some with larger engines.
I have IO360 (180HP) with FP prop. The airplane is lighter than most but is very satisfying to fly even with FP prop.
These are personal choices...its all a matter of what you want.
The RV-8...#83261 flying as of 6/16/2014
I'm in, dues paid 2017 This place is worth it!