I've been using the M2-ATX for a little over 3 weeks now, and haven't had any problems (yet.) I'm powering a full-size AMD64 3.5Ghz, 512MB DDR2, PNY FX5800 256MB video, 40GB Hard drive, USB Mouse, GPS, 120GB USB Hard Drive and my Motorola V3. Well, the only problem is when I'm not using the AC in the car it shuts down because of the heat, otherwise, no problems whatsoever.
I had to build my own P4 cable from 2 burned-out PSUs. I'll install a dedicated CPU fan on the M2 as soon as possible. I was going to suggest to use thicker wires on the positive/negative leads.