I have a .pdf of a German language "ProCycling" magazine wheel test. They ran 13 wheels on an indoor velodrome with a pro cyclist, recording the watts it took to hold a 45kph target speed. The Spline 32's were the lone "cheap, alloy" example in the test; everything else was carbon or carbon/alloy, and at least 40mm deep. They acquitted themselves quite well, at least in this low-yaw circumstance, essentially matching the Fulcrum Racing Quattro Carbons and the Dura Ace C50's. They came in about 9 watts higher than the best-in-test Swiss Side Hadron 625's and Roval CLX 64's.
"They're made of latex, not nitroglycerin"
"They're made of latex, not nitroglycerin"