Just a note on these kits, the L shaped plate the motor attaches to is flat. This works well on the pictured bike as it is carbon fiber and the front downbar is flat.
Most of you will have a round front bar and seat post bar (you can mount on either) and flat on round is not very stable. What I do is buy 2 muffler clamps the size of my front bar (or seat post depending on where I mount) and put a pair of the half clamp parts between the L plate.
Note you usually have to notch out the outside of the bolt holes as the plate spacing will be larger that the clamps holes but that's OK, it gives you to flat to round platforms and that gives you 2 darn near 360° clamps and 2 left over U bolts and that sucker ain't going anywhere ;-}