"Wheel pants on Cessna, Piper, Grumman, etc. do not increase the cruise
speed 10%. 3-5 knots is typical."

Depends, I got 7 knots out of my 16 pounds of wheel pants on my Cessna 152. I gladly put up with the weight increase. I also lost the nose break over stall characteristics by reducing the drag under the center of pressure. These may not be the wonder cure, but I'll try them. By the way, with the added weight to the nose, you might think of a Sky-tec starter. I replaced my Delco-Remy spur drive starter with a skytec and saved 10 pounds on the nose, starts faster too. That might make up for the future weight of the wheel fairings.