I tried the Concord 15/23 today with stock (86/96) and 85/88 nozzles. Feels pretty strong with the 85/88s, I might run this combo for a while. I didn't get to GPS at all, it was too choppy for any good readings (its always friggin choppy here). Felt pretty quick on the buoy course though and also when blasting in a straight line. Stock nozzles had a stronger initial punch from idle, but pinning it from ~1/4 throttle pulls a lot stronger with the 85/88s through mid and top end. Feels pretty noticeably better in the chop vs the straight blades on the stocker and XO.