I got lots of great recommendations for moving head instruments in a previous thread. As a result of the recommendations I received I have pretty much decided to purchase some Vari-lite VL1000s. The question I have is about which version I ought to get. I had the VL1000TSD recommended. The "T" stands for Tungsten which I definitely want. The "S" stands for shutter which sounds good but I am still considering going with the "I" for iris option. The "D" stands for dimmer. This is where I am really uncertain about what to do. What is the advantage of a moving head instrument having an onboard dimmer? Does the power for the instrument come through the DMX line? Why would I want or not want to have a dimmer on these instruments? Am I not understanding what the "dimmer" does? Thanks in advance for the help.