Remember that even though the M3s are rated at 175 watts, you will need nowhere near that much. They are rated to play at 96dB in a typical room when supplied with only 1 watt of power. Unless you plan on blasting your music at headache-inducing levels in your 150 sq ft room, that Marantz will handle the job nicely. Don't worry about a system's max wattage output too much. Just buy something that has the features you want.
You might be better served by going with an integrated amp and a separate player, though. That way you only have to replace the thing with moving parts when they wear out.
