Printrbot Metal Simple Spool holder and Z-rod Stabilizer

You may have noticed when moving the z axis at top speed, the z drive rod can make noise from whipping around. I found somebody had a z-axis stabilizer and I like that, and used it for a while. Then I optimized the design to use less material as I'm wont to do. I also designed a variety of spool holders, all of which work good, the last of them being quite optimized for that type of design. Then I got to thinking - why not combine both into one part? So I did. Best of my designs so far, and uses