Pescolar, glad you still are enjoying it. I thought that the 1578's were extremely dynamic, but started to give me some listener fatigue after a while. You really have to experiment with the Cary, but that is what makes it so good. It really doesn't need a matched quad and I found that it sounded better with different paired brands. Overall, I thought it sounded best to me when I used the Sylvania VT231's in the rear position and two ElectroHarmonix 6SN7's in the front. If I recall correctly Cary had Sino Chinese 6SN7's in it as the stock tube. Avoid them, they don't allow the SLP98 to shine at it's best.