The mainline kernel?

Do you understand how the Linux ecology works? Virtually all distributors of Linux-based OSes use kernels modified to suit their OSes. That is what you get from Canonical's repos.

You are free to mix and match whatever kernel you desire, but you had better know what you are doing.

You have strayed from the original subject of this thread. If you wish to get help, start another thread. And in your new thread, please do not simply dismiss the perfectly valid answers you have been getting from some very knowledgeable old hands. The issue here is not that you have not been answered. The issue is that you refuse to accept them.