Re: M8 spark plugs access
Depends on the bike!
I have a Softail Fat Bob which has the smaller fuel tank and you can get to both sets of plugs easily. So it's probably the same with the new Breakout and Street Bob models.
For the other bikes with larger tanks, you will probably need to remove the tank to get to the second set of plugs.
On the Fat Bob though, even removing the tank is easier as there is no longer any fuel crossover hose to remove.