@John Brown ... Re: @Drew...
I think you missed the point that Lexmark is arguing about a patent violation.
They are trying to protect their product and patent.
In the end, the law is on their side.
Now show me an aftermarket product that violates a patent, and I'll show you a lawsuit.
And if you want to see an example of where aftermarket parts make a difference, take a look at Remington Rifles and Browning. Remington 700s are the most popular bolt action rifles around. Why? Because you can customize them. Browning? Not so much. (THere's also the Ruger 10/22 but that's a different beast.)