oblgny, At the risk of appearing petty, the 3.5's come with an external equalizer or bass booster not a cross-over. Though the smooth impedance rise with it's insertion mitigates its total demand on amplifiers, it does put added demands on amplifiers none the less. The point being, extra power can be quite beneficial with these particular speakers.
It appears as though you might be able to use the Primare i22 with the 3.5's if you aren't using the tape loop for anything else.
Though it was some time ago, and the state of Class D amps might have progressed since then, Jim Thiel once told me that Class D amps were only suitable for subwoofers, and not competitive with traditional amps further up the frequency range.
If you like to try different gear with your Thiel 3.5's, I suggest you consider some iron fists in a velvet glove old school high out
put big iron: Krell, Threshold, etc.