Magnepan, How Low Can You Go...power-wise

Yes, the Simaudio 150wpc amplifier will drive them well and easily even being a nominal 4 Ohm load of impedance. Maggies have very low voltage sensitivity, somewhere around 85dB or so based on the model, so they require high wattage or at least current capability to produce moderate to high volume playback. A high current power amplifier will do better with them in general regardless of the brand or model. They also tend to respond better to solid state (like the Simaudio) than tubes depending on the brand and model of course. The Parasound A21 power amplifier at 250WPC RMS at 8 Ohms and 400 or so at 4 Ohms will not let you down with them at all. I know ... I have heard that combo many times at dealers and homes and it is effortless and beautiful sounding. Power with Maggies does what power to Usher Be-718's does ... brings them out and makes them live and sing like they can and should be able to. Don't make the mistake of skimping on the power and sheer kahunas under the hood with your maggies. For goodness sake, don't put a receiver on them of any kind; especially an A/V one. I heard that set up several times and it awful and constrained and lifeless at best.

In terms of bang for the buck, the $1200 NAD intergrated reviewed by Sam Tellig in Oct Stereophile seems hard to beat, and should do a very nice job with your 3,6's.

I keep being amazed by the responses to this. I want to know how many of these respondents have ever actually owned these speakers, and if so, how long did they keep them? If they used the dreadfully underpowered amps they have recommended I would assume it became very unsatisfying listening.

If you put that NAD integrated on a pair of 3.6r Maggies, it's not going to sound good. The amp may be fine with other speakers, but it's not going to bring those panels to life.

I have never owned them, but have sold them here in PA. Maggies need, or at least do so much better, with much high quality power on tap.

More power is better, but - If he powers them with the Sim amp in question he will be fine.
He'll get to Brazil, plop down on the couch with his favorite beverage and smile and be glad he bought the Maggies for a great price.
If he finds another ex-pat with 1000w monoblocks at a great price he should buy them as well. But the OP's question wasn't "What's better, 150w or 1000w to power Maggies?", which is where this thread has gone more or less.

btw: I've owned 12's and 1.6's for about 10 years, no longer have them.