im with ezra this is amazing work especially for it being hardsurface work… is this done completely inside of zbrush for the hard surface modeling? if so would love to see a video or a timelapse demonstrating your technique and workflow that you tend to use… 
have been trying to get into the hardsurface brushes for the longest time but still don’t understand the workflow so i use the clay buildup more than anything else to do my hardsuface work…