[pair of jacks]

Ok, I've got a 175 E-Tec with an aftermarket prop (stainless) 14 1/2 inch by 15 pitch. I'm getting wot at 5400 rpms with 80 gallons of fuel (capacity is 95) and just me aboard- 30 knots. Finding cruise is 24 kts @ 4800 rpms. People at Evinrude are telling me that I could get better performance with an Evinrude prop (either Viper or Rebel) due in part to a more curved blade giving better "grip". By the way, my boat is a 21.

Opinions??