Amplifier power supply voltage - moving between regions

I am considering getting an AirTight ATM 300R to pair with my Avantgarde Duo XDs. However, there is a practical issue. I live in Europe (230 V, 50 Hz), but expect to return to Canada (my home country, 120 V/60 Hz) in a couple of years. The amp comes from the factory in 100, 117 or 230 V models - the voltage is not selectable. I guess there are several options:

1. Get a 117 V model, and use a step up transformer while still in Europe - my preference, but unsure of the impact on sound quality, or if there would be other issues. Any thoughts on suitable transformers?
   
2. Get a 230 V model, and use a step-down transformer when I return to Canada - I don’t think so as it means using the transformer long term. Option 1 seems better, as long as there are no issues getting the 117 V model in Europe
3. Get a 230 V model, and return to the factory to get reconfigured to 117 V later. I am not sure if this is possible, or how much it would cost. Also a bit of a hassle.
4. Get a 230 V model, and sell it when I move. I don’t really want to go through the hassle of this, plus I may lose a fair amount of value in selling / re-buying.
5. Give up and look for an amp that has selectable voltage. However, these seem hard to find. Any thoughts on good models that have selectable voltage? 

FYI, my current amp is a Devialet Expert 220 which is multi-voltage. I recently acquired the Duo XDs, which have  built-in subwoofer amps with selectable voltage. The Devialet is OK with them but I am looking to step-up. So far I am really liking the sound of the AirTight amp and the idea of a SET amp.

I welcome your thoughts.