Originally Posted by ferball
I don't think those seats were ever intended to be sat on.
They're intended to be sat on while wearing padded cycling shorts so replacing them on a motorized bike is a very good idea.
For $269 you're getting close to bike shop prices for very low end bikes. You might want to go take a look at what a bike shop has to offer. With few exceptions, the cheapest bike at a bike shop is far and away a better value then the most expensive bikes at Walmart. It's like a quantum leap in difference.
Personally, I'd not spend a lot of money on a multi-gear bike if I planned to motorize it because most of the cost is being soaked up in components you will ultimately rarely use. You'd be better served buying a cheap bike and upgrading the necessary components (wheels, brakes, etc).
That said, it is important to have the ride that you like. If you're not happy with the base bicycle, you won't be happy with the motorized version.