You may not believe this, I know we were surprised when we got 57.6 MPH out of the 2008 Islandia. We checked it twice, upwind and downwind and that was the average. With the 310 HP package last year you were lucky to get over 48 MPH. We have found that speed to be consistant with all of the 2008 models we have sold. That is the same speed almost to the tenth that the 230 Challenger SE recorded as well. We also found that at cruise of 29 to 32 mph the 430 HP Islandia was running nearly 1,200 RPM less than the 310 HP package making it quieter. I'm guessing there is very little fuel consumption difference because of that fact as well. The bottom line is the 430 HP engine package is worth it!