delta drag
It's not the delta that will make a plane go fast, unless you are near the speed of sound, which most models are not even close. The low aspect ratio of a delta will make for more induced drag, if anything. Most airfoils have the best L/D with a lift coefficient of ~ 0.3. What a delta does do, is lower the structural weight requirement for a given strength. Less weight also means lower induced drag, so you'll have to figure out if the tradeoff from a higher aspect ratio wing is worth it.