It is a delta... the airfoil isn't going to matter much. Look at a Dust: it has no airfoil what so ever, and it still moves out pretty good. IMO the Phenom will be faster just because of the cowling, no doubt about it!

And as for weight: you will only notice that when pulling "G"s. On a straight line, I am quite sure you will not be able to tell one airfoil from another just by looking at the speeds. Maybe when you really start to time things...

A delta is just WAY too inefficient to tell which airfoil is better. The speed you gain during a dive just bleeds off so fast when pulling out! A good yank on the elevator acts as an emergency brake on these things! You might as well deploy a chute...