The Boeing was the plane that the P-40 replaced just before Pearl Harbor, about a year before, it was one of our front line fighters up until then.
Weight, yes it would add some weight but weight is nothing {within reason} to worry about. People are buying into this ARF thinking. They are selling very cheap light weight products and telling you it's how it should be, it's really just how it is. If you don't use any wood in a product it will come out light so they have to say something to sell people the idea.
In this case I removed a 4 stroke glow engine, added a 40cc gas engine and then removed three {3} pounds of lead out of the cowl to get the correct CG. I know {3} THREE POUNDS of lead!!! How can this be???
Simple, airplanes that are a scale of something can and will have some little problems. In this case the full scale plane had a big heavy round multi cylinder engine up front so it is short nose coupled to compensate for the weight of the round engine. In a model you have to add weight to compensate for that big round engine, lead is the normal way to do this.
Right now with the changes I made a smoke pump, tank and extra battery would be more of a help then a problem. By removing some of that lead it is slightly tail heavy now, the extra gear would go up front and put the CG right back to neutral.
In my case the tail heavy CG will add to my fun and if it gets away from me then just look at all the extra gear I would have for another plane!!!