I have a Pioneer 106D which I wish to install in my computer. I have a CD reader. Should I put the DVD Burner on the same cable as the CD Reader?
Which should be the master?

No point to have the CD reader anymore. While Pioneer 106D is a slow DVD producer (4x write) comparing to the newer ones which write at 16x or 18x - it will read any CD or DVD.
You probably have an older motherboard with 2 IDE connectors. So if you want to keep both
of them - you could have DVD as master, but would not make any difference. You are not going to use the CD reader and burning DVD or CD the same time.
This is a good DVD burner-although slow-that will not produce coasters.
Cheeers.

I agree with making the new drive the master. But, if you copy CDs, it will be easier to do with 2 drives. I would put them both on the same cable.