When you have a wider contact patch, you are going to feel the road more. Still, there shouldn't be any major vibration. I have gone through a set of 265 and 285 on my car, none of them vibrate much more than stock, but I could feel the road more.
Watch from the 10 sec mark to 16 sec. I had one hand on the wheel going 80+, no noticeable vibration back and forth.
0611 CART Lime Rock Park GT3 Rain - YouTube
If your tire guy is correct, all the sports cars would be vibrating like a vibrator since they all have huge tires!