This is an exciting lab. If you have done something wrong in GRUB loader, you may have big problem on loading new kernel. But of course you can always boot your old kernel and trouble shoot it.
In this lab I learned how to customise your kernel. We downloaded the kernel source from the internet and customise the GRUB to boot the new kernel.
Customising kernel is an important thing. You can customise your Fedora Linux kernel with loading an driver during boot. This is very important for a lot of linux user, since a lot of Linux users has problem with Vista based hardware device, which may not supported for a fresh installed Fedora Linux. So, you can put your driver in the kernel and you can use your hardware in your Fedora Linux.
Another thing about customising kernel is you can pack your customised kernel source in to a tar ball, and next time when you have an fedora install again, instead of downloading and install the driver again, you can just un-tar the old kernel and load it again.
When other operating system give you a fancy interface, on top of fancy interface, linux provide a flexible OS for you, so you can do any changes any time you want.
Freedom... this is what Linux about.