The general rule of thumb for PC games is that the average person can't tell the difference in speed until 10% difference*...I expect that the same would apply in this case. In fact, for most non-real-time applications, would probably take more than 10% difference to notice. Now, going from the 1.83 to the 2.0 has a lot of other benefits than just clockspeed, but jumping up to the 2.16 is purely a clockrate jump.
I suspect that if money is any kind of consideration, that the 2.16 is not worth the premium over the equally configured 2.0 model.
* this is speaking from an FPS perspective, all else being equal.