OK. Got some numbers for you guys. We are experiencing extremely warm temps here in South Jersey this December. (68?) So my two sons, ages 8 and 11, decided that we had done all this work and had not gotten to run the boat. As I mentioned earlier, I boat the boat without ever running it but I knew who I had bought it from, and I know he's not much on Maintenance, I also knew he hadn't used it much and really didn't hurt anything. Here's a brief run down: 2003 sea Ray 176 3.0 with alpha 1 gen 2. Boat wieghs in at 2300, with all of us (2-200lbs men and 2-60lbs kids and maybe 150lbs of gear) around 3000lbs we'll say. Over the last few months we've rebuilt the carb, changed plugs, dismantled lower unit changed all water pumps components, sanded primed and painted the whole thing, remounted, added a new four blade Mercury spitfire (14x21) changed thermostat housing and a few other things.... Oh! Added the smart tabs! Well started off well and got about 1/4mile from the dock and blew the thermostat housing gasket that I just replaced..... Luckily I was able to us my baseball hat as somewhat of a gasket to limp back to the ramp. Then out of dumb luck, the marina I was at happen to have a new one. About an hour later with a new gasket and some gasket rtv this time, we were back on the water. Cruiesd at 3600 rpm running 31 mph. We ran 20 miles and I gotta say the smart tabs were a smart choice. Ran it hard on the way home (40mile round trip) for a short stretch and got 42mph at 4800 rpms which puts my prop slip around 15% which I think is a pretty good number. So I still have to throw the original three blade back on and compare but I doubt there will be much difference other than it might take a lil longer to plan and we may get a couple mph on the top end. All and all I'm very happy with the new Mercury spitfire and the smart tabs. Hope this helps everyone.