Here's picture of both my LaStik's. The red one started out as electric, with dihedral and a EFlite Park 250 motor. I switched it to a Cox .020. It flew good with the .020, but after having throttle, and alot longer flite time, and no cleanup, it wasn't as fun for me. Not saying it wasn't fun to fly, I just preferred the electric version.
The purple one is without dihedral and a Turnigy 2211 The wife made me remove the crosses and put the teddy bears on it for her!
I would not try to use the 400 way to big and heavy, the Turnigy is more than enough power with a 2s 7.4V 320Ma 25c battery.
Edit: The motor was a Eflite Park 250, not 280.