Question about amplifier input sensitivity

I'd like to use my Wadia di122 DAC as a preamp and I've been looking for amps that have an input sensitivity > 2 volts - which is what Wadia recommends.  Their actual quote in the manual is this: "...due to a wide range of power amplifier designs, it is important the input sensitivity of the amplifier be at least 2 volts.  This will assure the playback of of most music recordings are reproduced with adequate dynamic range."   

I've researched about ten amps and they all range from 1 - 1.5 volts.  The only two amps I found that were at least 2 volts were Mark Levinsons which are way out of my price range.

Is this a recommendation that I really need to follow?  Are they suggesting that there won't be enough gain from "lesser" amps?  The only other relative specs I have for the Wadia, per the manual, are a variable output level of 0.0-4.0 Vrms for the unbalanced outputs and 0.0-8.0 for the balanced outputs.  I'm not sure this matters, but the output impedance is less than 100 ohms for both balanced and unbalanced sections.

Is something I really need to worry about when looking for an amp?  FWIW, I was looking at a PrimaLuna Prologue Four which has an input sensitivity of just 600 mVrms!  

Thanks in advance for any help or advice on this subject.