Does it make any difference in burn quality or sound quality?
Probably not. You will never get the best results on a high-speed burner, using high-speed media, and burning at low speed. Burn at 32x to 40x on high-speed media and be happy.
On high speed drives, using 40x/48x media, you will higher error rates when burning at <20x speed.
But there's an easy way to find out for yourself, test them each way and see.