Beenie, speed comes from a sleek shape and slippery airfoil with the overall size of the model being of a secondary concern as to speed. 300 is a step in the right direction but it would still offer a lot of problems in your one engine out situation.

But of course thanks to those huge engine nacelles and relatively large fuselage you sure don't have the sleek shape. I know I looked at the X5F a couple of years ago and put it on the back burner as far as a glow engine model went. I just could NOT get enough wing area to satisfly my wing loading needs without the cowls being so large that onely the last inch of prop stuck out past the cowl opening..... not the outside diameter but the opening in front of the cowl. At that point I figured that this was a model best used for gear drive props and electric motors.