I own both. I have the WM .40 size P51 with a ST 90 in it. It is a nice plane but it is a "Sportscale." I am assembling the Hangar 9 and by looks it is more of a scale plane. IMHO, Both are nice planes but I have to give you the Hangar 9. Most power them with a .90 something or 100ish FS. Me, I am stuffing a Saito 150 in it. Later