A few lighter (plastic) props certainly wouldn't hurt and arguably wouldn't increase the speed any.

The plastic props save more time than money. By the time you field a competitive Q-40 ship (usually composite) you've got nearly a grand into it, anyway. $10 props aren't going to make that much of a difference (if you can buy wooden ringers for $35-$50). I've got a pitch gauge and a bunch of blanks but I'd rather spend my time building and flying than carving props. Take that back....I'd rather spend my time doing ANYTHING but carving wood props. Most of mine end up as glue sticks, anyway.

Yes, I believe that those who can carve good wood props may have a slight advantage (all else being equal). The fact is, though, that those guys going fast with wood props also have the airframe/engine/flying skills to utilize whatever advantage the better prop may offer. Ya still gotta fly the plane.....

Once I believe that I'm putting everything on the course (not quite there yet) I'll spend the time experimenting with props. Right now I'm afraid it would be a waste.