Personally, I don't feel unsafe. But each person's gotta make his/her own call on that question as it applies to them. Just because I feel fine at that speed doesn't mean that everyone should.
Here's my opinion: Motorcycles are dangerous. Motorcycles at 170 MPH are probably more dangerous than ones that are not. Public roads aren't the best place to be doing this sort of thing. If you're gonna ride like that, keep your skill levels up by spending some time (regularly) on the race track, wear good gear (head to toe), keep the bike in tip-top condition, and don't be antisocial.
Some other thoughts - do it on a piece of good road you know in daylight. One free of cars and animals (and cops
). Oh yeah, don't try it if you've had even one beer - the attitude change will get you in trouble every time! (Learned the hard way - twice!)
I'm sure that others will come up with more wisdom - or may simply tell you and everyone else within shouting distance that we're all a bunch of suicidal wackos.
As far as the bike is concerned, I think it's not bad at those high speeds, but I've ridden other bikes that felt more "planted" and gave a little more confidence.