Simple Swerve/Crab

[Rob2713g]

After reading numerous threads and ideas, I had a few questions about swerve and crab drive.

Did anyone use a Banebots gearbox in their swerve assembly this year?

What material is best for making a module? And in what thickness? I noticed some people used Delrin, while others used metal. If you used Delrin, would you need bearings?

What are the advantages to having the modules set up in pairs, as opposed to having one motor control the direction of all 4 wheels?

What size are your modules and how do you have them supported to protect them?

Thanks in advance!