Well, according to what I've done when compiling my kernels (I've done it a few times..heheh) I'd say you need to
make menu(or whatever)config
cp where-ever-you-are/arch/i386/boot/bzImage /boot/whatever-you-use
cp where-ever-you-are/System.map /boot/System.map
and that's it. make clean "cleans" the installation, and isn't that way necessary for the kernel to work - still, if you like cleaning, do it
I guess many do. Copying config isn't needed, I think....why would it be?
So bzImage is the kernel image, and you need it if you wish to boot it
if you have selected anything to be compiled as modules, you need to "make modules" and then install them via "make modules_install"... System.map is, as it's name tells, a map of System (haven't checked out it that well, but I'd say it's needed) and...initrd is "initial ram disk", and at least I don't ever copy or make that one. Not on a normal kernel compilation, that is
and do the "clean" if you wish, but it won't basically affect your kernel's compilation.
I no more use LILO, haven't used it for a while because I didn't like it's "you mus rerun lilo-stuff every time you do something to your kernel"
grub doesn't ask that..just to update it's config & boot. not a big deal, but well....I've learnt to like grub, even though LILO was a good friend earlier.