Let me take a guess at reality.
After you pay for the kit, an order is placed for a front and rear off-the-shelf 9C motor in whatever wind (he has not idea what would be optimal anyhow). Maybe alters phase wires at least? (or maybe better left stock...)
A pair of controllers is hopefully purchased from Lyen (we've seen his soldering skills...)
Throttle, battery (hopefully something professionally assembled from Cell_man) and other bits are purchased.
Parts are shipped to buyer. The buyer assembling it is going to be baffled by the inherent issues of running two controllers off a common throttle (which requires a clever method to ground-isolate or they don't function correctly together).
If buyer tries to use even half that power level in the front hub, it's going to be a critical life-safety issue. If you use a suspension fork, unless an elaborate custom sleeve is created to distribute the torque to a higher point on the fork, the fork is going to work-harden and fail over time, even if the bolts never loose tension etc. If you run a steel rigid fork, it can be strong enough, but riding a bicycle at 40-50mph with no front suspension simply equals a serious injury pending (yet likely less severe than if the end breaks off a suspension fork).
If you look over the history of the 2wd bike you copied the videos from, you will notice the first version was a lameo chopper style bike, spun it's hub out multiple times, got wrenches welded onto the steel fork for torque arms, and then shortly after the fork broke. Then onto the cruiser bike, elaborate custom torque-arms from strong wrenches welded together and proper fasteners. Ripped the fork drop-outs and came off in the very video you copied (and edited out that part).
We called this sufficient testing on the 2wd concept to call it a failure (because a front hub is suitable for low-power ONLY), as going to the rear motor alone eliminated the failures, made handing loads better, and had no performance difference from just dumping the power into a ventilated rear hub.
If you want to do something special, learn the art of winding a motor, vent the covers (in a way that minimally weakens them) and silicone a mesh screen in place to prevent objects from getting into the flux-gap area. Then hand-wind a copper-fill optimized wind on a hub laying each turn in by hand with 200C rated wire, then rip out the halls, replace with real honeywell halls that are reliable and have a high temp limit, solder them in with high temp solder and teflon jacketed wire, and mount a thermistor inside the motor attached with silicone to the back of the copper end-turns. Run 10awg phase leads out of the axle, and pot every possible chafe point with a high temp flexible epoxy on both ends, then terminate with some 6-8mm barrel connectors.
Then you've got a motor that would be greatly more efficient, and easily have 2-3x the continuous power handling of a stock 9c, and it would be worth paying the 500% mark-up for.
...
, and just seriously learn and contribute to ES in ONLY A POSITIVE WAY from now on... I don't think you should be selling anything "eBike related" for the time being considering what has just happened by your doing...
