Welcome to the forums, yo! Now I'm not the most qualified to talk on motors yet, as I have very limited experience, but I'm willing to bet you'll need at least a Tz85a for scooter motors. 30a ESCs won't cut it, and you may even need something more powerful than an 85, depending on what you use. If you want, you can buy the Tz85 brushless version off HobbyKing, and mod it to be brushed using this guide. Anyway, hope you have fun building, and I'm sure plenty more people will have important advice for you too.