The park 46 doesnt like to be pushed on 5s at all. I killed 2 of the with just a 12x8 prop on 5s = alittle over 900watts. My(cheaper) hxt 50x55 600kv handled the 15x8 and 1300watts. From what I hear scorpion motors are top notch and the specs on that one look awsome. There is a huge thread on this plane over on rcgroups.com in the 3d section.

I used the hs225mg servos for this plane and they worked great(more than enough power as well as very light)

If it was me to keep weight down I would go with the Scorpion 3026-12 on 4s with say a 13x6.5 to 13x8 prop. The plane would only be around an auw of 4 pounds and thats about 200watts a pound(lots of power to do anything) with that motor. You really want to keep it light as possiable or you will have unwanted snap tendencies.