I don't know the input impedance of the Acurus. Tube preamps can have a highish output impedance, especially in the bass, and if mated with a power amp with a lowish input impedance (typically solid state), then the bass will roll off early. Once you know the input impedance of the Acurus, you'll want to learn the worst case impedance of the preamp to ensure it's not too high relative to the Acurus.
Based on the impedance graph of the M20 in Stereophile, a solid state amp is probably a good fit. So as long as you're aware of the impedance matching issues with your amp, any preamp will work well with the M22. As MrTennis said, it's personal preference.
Here's a quote from an $18K preamp review. Note the last two sentences.
The input impedance was very high, at 470k ohms or more at low and midrange frequencies, dropping to 163k ohms at 20kHz. (These figures are approximate because of the large margin of error when measuring AC impedances this high.) The Rex will therefore not load down source components at all. However, its output impedance was a little higher than specified, at 1000 ohms at 20kHz, 415 ohms at 1kHz, and 4.8k ohms at 20Hz. The last is due to the necessarily finite size of the output coupling capacitors. As MF noted, it should not be a significant issue in listening to music as long as the power amplifier has an input impedance greater than about 50k ohms. (BAT's own power amplifiers have input impedances well above 100k ohms.)http://stereophile.com/tubepreamps/208bat/index4.html