I can tell you first hand the vibration is not normal. My wife and I bought 2 brand new 2014 450's with eps and one is very smooth very little vibration, the other has a ton of vibration form about 18 to 27 miles an hour, and when you gas it from about 7 miles an hour. I am going to take it back to have it looked at, I am guessing something with the belt cause the one without vibration accelerates alot better.

 

The vibration is from the high rpms when cruising..The 450 engine is known for being noisy and loud...it's normal highest rpm is 7-11 mph