There are a lot of factors, but unless you're riding either behind a large windscreen or on a naked bike with a really quiet helmet the noise levels will probably be damaging at highway speeds. Most helmets that aren't Shoei, Arai or Schuberth will not be quiet enough on their own.
The Versys stock windscreen is particularly bad for noise levels too. I find myself needing earplugs for any sustained riding above 70mph on mine, with a HJC helmet that is about average in noise level. On my Suzuki Bandit the screen was much better from a clean air standpoint and my old helmet was fairly quiet and earplugs weren't really needed most of the time (windy days or longer highway rides were still borderline).
Earplug wise, I just use the cheap foam ones, they do the job and I can get all the ones I could ever want for free from where I work (I work in a datacenter which is noisy enough in areas to need hearing protection, I use a noise cancelling headset for hearing protection at work, but will grab plugs out of the earplug dispensers for riding).
Last edited by mrvwbug; 10-20-2017 at 11:51 PM.