Wet performance (in rain that is hard enough to maintain standing water) is all about hydroplain resistance. This is directly related to tread depth. Any of our street tire options (PS1, PS2, PSS, NT05, INVO, KDW, KumhoXS) will perform better in rain at full tread depth than the next tire at 50%
With wet roads(from damp to a light rain) the overall performance is more related to the tire compound. A PS2 shaved to 25% could possibly perform better than an INVO or KDW at 100% in this situation. I dont know for sure though. Just wanted to comment on the diff between the two diff rain/wet roads situations.