Paulu, you've decided on a solid state integrated amp, so I won't suggest tube amps even if they will sound better with the M3s. There are those who say amps have no real effect on the sound produced. If you are comfortable with that theory then get the cheapest amp of whatever output you can find - your best bet probably used.

Are you adventurous? An early adopter? I know which solid state amp I've been thinking about trying - The Flying Mole. Yes, that's right, the Flying Mole - not integrated - monoblocks which are said to sound like a good tube amp.

Here's a review:
http://www.stereotimes.com/amp021804.shtm

Here's a picture:


Here's the Japanese website for Flying Mole
http://www.flyingmole.co.jp/en/products/dadm100pro/index.html

Of course you have to beware of a stiff breeze as they only weight 1.4 lbs each.


Enjoy the Music. Trust your ears. Laugh at Folks Who Claim to Know it All.