There is nothing wrong with selling something for more than you paid for it. A 40% markup is average for slow moving low competition parts. A 110% markup is pretty steep, but if people choose to buy everything in one convenient place that has stock and they don't choose to shop around, that's fine too.
Advertising things as better than they are, I have an issue with. If you really did improve them, great!
But please spill the beans as to what was upgraded. I've used those flash modules with incredibly tiny 24-26 gauge wire in them and powered 30+ watt LED light bars with them for hours on end without failure. Was I taking risks? Sure, but it was for a demo and if it melted down it wasn't going to injure kids.
You really need to offer a scooter controller kit. You can easily source it from China like everyone else does. Then when offering your Level XXIX1000 upgrade kit you can specify that voltages 18 and up without your scooter controller greatly reduces the lifespan of components. If they choose to upgrade properly you get a sale and the customer gets better results. If they choose to go for the "big numbers" without the proper underlying upgrades they will do so having at least acknowledged the impending failures and they would bare the brunt of the responsibility.
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"I've stood on the shoulders of geniuses, and taken the next step..." Master Project List
(F150 6x6, 36v Superpower, 24v Beach Ranger 4x4, McQueen "El Relampago", 36v Polaris, Mudvette, Lil jeep dragster & mudder, 36v Rzr, Lifted Cowboy's jeep, FJ cruiser, Lil quad 18v, etc...)Toycrushers Master Wiring Diagrams