Generally, yes, you should be able to add in whatever kernel rpm you want.
There are some gotchas I can think of off the top of my head:
- have a backup of your really important data (preaching to the chior, I hope)
- make sure you install, not upgrade the new kernel and modules rpm -ivh kernel-blah.arch.rpm to make life easier to boot the old kernel, should you need
- make sure you upgrade to a compatible version of modutils
- check /etc/yum.conf to exclude those packages you install above from being automagically upgraded when you do a yum update
If you do that, you should have no problem. If there are any other dependencies that rpm asks for, (shouldn't be, but you never know,) take a long hard look to make sure you don't install something that conflicts with your other kernel.
You know, on second thought, you may run into some dpendencies that rpm won't know about if you are using LVM, md, etc. but those generally are not a big deal.
(and yes, IAARHCE!)