Two schools of thought on the write speed.
Some feel the slower the better. I used to be a member of that group, because it seemed to hold true. I have come to believe it was true at one time, but possibly related to the available media.
The other group says the faster the better. Some on the forums have reported that fast writing has improved the quality and eliminated "sticking Letters" in commercial cdg's. I can't speak for that.
I do know however that I am able to produce error free cdg's time after time running wide open at 48X as long as I stick to Mitsui Silver media.
Experiment for yourself and take whatever course works for you, and that you're comfortable with.
George